1
|
Mong MA. Vitamin K and the Visual System-A Narrative Review. Nutrients 2023; 15:nu15081948. [PMID: 37111170 PMCID: PMC10143727 DOI: 10.3390/nu15081948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 04/29/2023] Open
Abstract
Vitamin K occupies a unique and often obscured place among its fellow fat-soluble vitamins. Evidence is mounting, however, that vitamin K (VK) may play an important role in the visual system apart from the hepatic carboxylation of hemostatic-related proteins. However, to our knowledge, no review covering the topic has appeared in the medical literature. Recent studies have confirmed that matrix Gla protein (MGP), a vitamin K-dependent protein (VKDP), is essential for the regulation of intraocular pressure in mice. The PREDIMED (Prevención con Dieta Mediterránea) study, a randomized trial involving 5860 adults at risk for cardiovascular disease, demonstrated a 29% reduction in the risk of cataract surgery in participants with the highest tertile of dietary vitamin K1 (PK) intake compared with those with the lowest tertile. However, the specific requirements of the eye and visual system (EVS) for VK, and what might constitute an optimized VK status, is currently unknown and largely unexplored. It is, therefore, the intention of this narrative review to provide an introduction concerning VK and the visual system, review ocular VK biology, and provide some historical context for recent discoveries. Potential opportunities and gaps in current research efforts will be touched upon in the hope of raising awareness and encouraging continued VK-related investigations in this important and highly specialized sensory system.
Collapse
Affiliation(s)
- Michael A Mong
- Department of Ophthalmology, Veteran Affairs North Texas Health Care Medical Center, Dallas, TX 75216, USA
| |
Collapse
|
2
|
Variant Landscape of 15 Genes Involved in Corneal Dystrophies: Report of 30 Families and Comprehensive Analysis of the Literature. Int J Mol Sci 2023; 24:ijms24055012. [PMID: 36902444 PMCID: PMC10003302 DOI: 10.3390/ijms24055012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 02/27/2023] [Accepted: 03/03/2023] [Indexed: 03/08/2023] Open
Abstract
Corneal dystrophies (CDs) represent a group of inherited diseases characterized by the progressive deposit of abnormal materials in the cornea. This study aimed to describe the variant landscape of 15 genes responsible for CDs based on a cohort of Chinese families and a comparative analysis of literature reports. Families with CDs were recruited from our eye clinic. Their genomic DNA was analyzed using exome sequencing. The detected variants were filtered using multi-step bioinformatics and confirmed using Sanger sequencing. Previously reported variants in the literature were summarized and evaluated based on the gnomAD database and in-house exome data. In 30 of 37 families with CDs, 17 pathogenic or likely pathogenic variants were detected in 4 of the 15 genes, including TGFBI, CHST6, SLC4A11, and ZEB1. A comparative analysis of large datasets revealed that 12 of the 586 reported variants are unlikely causative of CDs in monogenic mode, accounting for 61 of 2933 families in the literature. Of the 15 genes, the gene most frequently implicated in CDs was TGFBI (1823/2902, 62.82% of families), followed by CHST6 (483/2902, 16.64%) and SLC4A11 (201/2902, 6.93%). This study presents, for the first time, the landscape of pathogenic and likely pathogenic variants in the 15 genes responsible for CDs. Awareness of frequently misinterpreted variants, such as c.1501C>A, p.(Pro501Thr) in TGFBI, is crucial in the era of genomic medicine.
Collapse
|
3
|
UbiA prenyltransferase domain-containing protein 1 (UBIAD1) variant c.695 A > G identified in a multigenerational Japanese family with Schnyder corneal dystrophy. Jpn J Ophthalmol 2023; 67:38-42. [PMID: 36367598 DOI: 10.1007/s10384-022-00951-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/25/2022] [Indexed: 11/13/2022]
Abstract
PURPOSE We aimed to identify pathogenic variations in the UbiA prenyltransferase domain-containing protein 1 (UBIAD1) gene in a Japanese family with Schnyder corneal dystrophy (SCD). STUDY DESIGN Clinical study METHODS: Three clinically diagnosed SCD patients from a single pedigree participated. Patients 1 and 2 were 69- and 65-year-old sisters, and patient 3 was the 42-year-old daughter of patient 1. Blood samples from the patients were obtained for genetic analysis. Mutation screening of the two UBIAD1 exons was performed using polymerase chain reaction (PCR)-based DNA sequencing. RESULTS All participants were found to be heterozygous for the pathogenic missense variation c.695 A > G (p.Asn232Ser) in exon 2 of UBIAD1. CONCLUSION This is the first report on the pathogenic UBIAD1 variation c.695 A > G (p.Asn232Ser) in a Japanese population. SCD is a rare corneal dystrophy, and further research on additional cases will aid in the elucidation of disease mechanisms and development of therapeutic strategies.
Collapse
|
4
|
Dias-Teixeira KL, Sharifian Gh M, Romano J, Norouzi F, Laurie GW. Autophagy in the normal and diseased cornea. Exp Eye Res 2022; 225:109274. [PMID: 36252655 PMCID: PMC10083687 DOI: 10.1016/j.exer.2022.109274] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/23/2022] [Accepted: 09/29/2022] [Indexed: 01/18/2023]
Abstract
The cornea and covering tear film are together the 'objective lens' of the eye through which 80% of light is refracted. Despite exposure to a physically harsh and at times infectious or toxic environment, transparency essential for sight is in most cases maintained. Such resiliency makes the avascular cornea a superb model for the exploration of autophagy in the regulation of homeostasis with relevancy to all organs. Nonetheless, missense mutations and inflammation respectively clog or apparently overwhelm autophagic flux to create dystrophies much like in neurodegenerative diseases or further exacerbate inflammation. Here there is opportunity to generate novel topical therapies towards the restoration of homeostasis with potential broad application.
Collapse
Affiliation(s)
| | | | - Jeff Romano
- Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
| | - Fatemeh Norouzi
- Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
| | - Gordon W Laurie
- Department of Cell Biology, University of Virginia, Charlottesville, VA, USA; Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA; Department of Ophthalmology, University of Virginia, Charlottesville, VA, USA.
| |
Collapse
|
5
|
Souzeau E, Siggs OM, Mullany S, Schmidt JM, Hassall MM, Dubowsky A, Chappell A, Breen J, Bae H, Nicholl J, Hadler J, Kearns LS, Staffieri SE, Hewitt AW, Mackey DA, Gupta A, Burdon KP, Klebe S, Craig JE, Mills RA. Diagnostic yield of candidate genes in an Australian corneal dystrophy cohort. Mol Genet Genomic Med 2022; 10:e2023. [PMID: 35985662 PMCID: PMC9544209 DOI: 10.1002/mgg3.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 07/18/2022] [Indexed: 11/09/2022] Open
Abstract
Corneal dystrophies describe a clinically and genetically heterogeneous group of inherited disorders. The International Classification of Corneal Dystrophies (IC3D) lists 22 types of corneal dystrophy, 17 of which have been demonstrated to result from pathogenic variants in 19 identified genes. In this study, we investigated the diagnostic yield of genetic testing in a well‐characterised cohort of 58 individuals from 44 families with different types of corneal dystrophy. Individuals diagnosed solely with Fuchs endothelial corneal dystrophy were excluded. Clinical details were obtained from the treating ophthalmologist. Participants and their family members were tested using a gene candidate and exome sequencing approach. We identified a likely molecular diagnosis in 70.5% families (31/44). The detection rate was significantly higher among probands with a family history of corneal dystrophy (15/16, 93.8%) than those without (16/28, 57.1%, p = .015), and among those who had undergone corneal graft surgery (9/9, 100.0%) compared to those who had not (22/35, 62.9%, p = .041). We identified eight novel variants in five genes and identified five families with syndromes associated with corneal dystrophies. Our findings highlight the genetic heterogeneity of corneal dystrophies and the clinical utility of genetic testing in reaching an accurate clinical diagnosis.
Collapse
Affiliation(s)
- Emmanuelle Souzeau
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Owen M Siggs
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia.,Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Sean Mullany
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Joshua M Schmidt
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Mark M Hassall
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia
| | | | - Angela Chappell
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - James Breen
- South Australian Genomics Centre (SAGC), South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia.,Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia.,Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | - Haae Bae
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia
| | | | | | - Lisa S Kearns
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Sandra E Staffieri
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia.,Department of Ophthalmology, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Alex W Hewitt
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
| | - David A Mackey
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia.,Centre for Ophthalmology and Visual Science, University of Western Australia, Lions Eye Institute, Perth, Western Australia, Australia
| | - Aanchal Gupta
- South Australian Institute of Ophthalmology, University of Adelaide, Adelaide, South Australia, Australia.,Adelaide Eye & Laser Centre, Adelaide, South Australia, Australia
| | - Kathryn P Burdon
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia.,Centre for Ophthalmology and Visual Science, University of Western Australia, Lions Eye Institute, Perth, Western Australia, Australia
| | - Sonja Klebe
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Jamie E Craig
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Richard A Mills
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia
| |
Collapse
|
6
|
Chen H, Qi X, Faulkner RA, Schumacher MM, Donnelly LM, DeBose-Boyd RA, Li X. Regulated degradation of HMG CoA reductase requires conformational changes in sterol-sensing domain. Nat Commun 2022; 13:4273. [PMID: 35879350 PMCID: PMC9314443 DOI: 10.1038/s41467-022-32025-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 07/12/2022] [Indexed: 01/20/2023] Open
Abstract
3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) is the rate-limiting enzyme in cholesterol synthesis and target of cholesterol-lowering statin drugs. Accumulation of sterols in endoplasmic reticulum (ER) membranes accelerates degradation of HMGCR, slowing the synthesis of cholesterol. Degradation of HMGCR is inhibited by its binding to UBIAD1 (UbiA prenyltransferase domain-containing protein-1). This inhibition contributes to statin-induced accumulation of HMGCR, which limits their cholesterol-lowering effects. Here, we report cryo-electron microscopy structures of the HMGCR-UBIAD1 complex, which is maintained by interactions between transmembrane helix (TM) 7 of HMGCR and TMs 2-4 of UBIAD1. Disrupting this interface by mutagenesis prevents complex formation, enhancing HMGCR degradation. TMs 2-6 of HMGCR contain a 170-amino acid sterol sensing domain (SSD), which exists in two conformations-one of which is essential for degradation. Thus, our data supports a model that rearrangement of the TMs in the SSD permits recruitment of proteins that initate HMGCR degradation, a key reaction in the regulatory system that governs cholesterol synthesis.
Collapse
Affiliation(s)
- Hongwen Chen
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaofeng Qi
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Rebecca A Faulkner
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Marc M Schumacher
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Linda M Donnelly
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Russell A DeBose-Boyd
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Xiaochun Li
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| |
Collapse
|
7
|
Elsabrouty R, Jo Y, Hwang S, Jun DJ, DeBose-Boyd RA. Type 1 polyisoprenoid diphosphate phosphatase modulates geranylgeranyl-mediated control of HMG CoA reductase and UBIAD1. eLife 2021; 10:64688. [PMID: 34842525 PMCID: PMC8641950 DOI: 10.7554/elife.64688] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 11/28/2021] [Indexed: 11/18/2022] Open
Abstract
UbiA prenyltransferase domain-containing protein-1 (UBIAD1) utilizes geranylgeranyl pyrophosphate (GGpp) to synthesize the vitamin K2 subtype menaquinone-4. The prenyltransferase has emerged as a key regulator of sterol-accelerated, endoplasmic reticulum (ER)-associated degradation (ERAD) of HMG CoA reductase, the rate-limiting enzyme in synthesis of cholesterol and nonsterol isoprenoids including GGpp. Sterols induce binding of UBIAD1 to reductase, inhibiting its ERAD. Geranylgeraniol (GGOH), the alcohol derivative of GGpp, disrupts this binding and thereby stimulates ERAD of reductase and translocation of UBIAD1 to Golgi. We now show that overexpression of Type 1 polyisoprenoid diphosphate phosphatase (PDP1), which dephosphorylates GGpp and other isoprenyl pyrophosphates to corresponding isoprenols, abolishes protein geranylgeranylation as well as GGOH-induced ERAD of reductase and Golgi transport of UBIAD1. Conversely, these reactions are enhanced in the absence of PDP1. Our findings indicate PDP1-mediated hydrolysis of GGpp significantly contributes to a feedback mechanism that maintains optimal intracellular levels of the nonsterol isoprenoid.
Collapse
Affiliation(s)
- Rania Elsabrouty
- Department of Molecular Genetics, University of Texas Southwestern Medical Center at Dallas, Dallas, United States
| | - Youngah Jo
- Department of Molecular Genetics, University of Texas Southwestern Medical Center at Dallas, Dallas, United States
| | - Seonghwan Hwang
- Department of Molecular Genetics, University of Texas Southwestern Medical Center at Dallas, Dallas, United States
| | - Dong-Jae Jun
- Department of Molecular Genetics, University of Texas Southwestern Medical Center at Dallas, Dallas, United States
| | - Russell A DeBose-Boyd
- Department of Molecular Genetics, University of Texas Southwestern Medical Center at Dallas, Dallas, United States
| |
Collapse
|
8
|
Chen X, Furukawa N, Jin DY, Liu Y, Stafford DW, Williams CM, Suhara Y, Tie JK. Naturally occurring UBIAD1 mutations differentially affect menaquinone biosynthesis and vitamin K-dependent carboxylation. FEBS J 2021; 289:2613-2627. [PMID: 34813684 PMCID: PMC9064899 DOI: 10.1111/febs.16291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 10/15/2021] [Accepted: 11/22/2021] [Indexed: 11/30/2022]
Abstract
UbiA prenyltransferase domain-containing protein-1 (UBIAD1) is responsible for the biosynthesis of menaquinone-4 (MK-4), a cofactor for extrahepatic carboxylation of vitamin K-dependent (VKD) proteins. Genetic variations of UBIAD1 are mainly associated with Schnyder corneal dystrophy (SCD), a disease characterized by abnormal accumulation of cholesterol in the cornea. Results from in vitro studies demonstrate that SCD-associated UBIAD1 mutations are defective in MK-4 biosynthesis. However, SCD patients do not exhibit typical phenotypes associated with defects of MK-4 or VKD carboxylation. Here, we coupled UBIAD1's biosynthetic activity of MK-4 with VKD carboxylation in HEK293 cells that stably express a chimeric VKD reporter protein. The endogenous Ubiad1 gene in these cells was knocked out by CRISPR-Cas9-mediated genome editing. The effect of UBIAD1 mutations on MK-4 biosynthesis and VKD carboxylation was evaluated in Ubiad1-deficient reporter cells by determining the production of MK-4 or by measuring the efficiency of reporter-protein carboxylation. Our results show that the hot-spot mutation N102S has a moderate impact on MK-4 biosynthesis (retained ˜ 82% activity) but does not affect VKD carboxylation. However, the G186R mutation significantly affected both MK-4 biosynthesis and VKD carboxylation. Other mutations exhibit varying degrees of effects on MK-4 biosynthesis and VKD carboxylation. These results are consistent with in vivo results obtained from gene knock-in mice and SCD patients. Our findings suggest that UBIAD1's MK-4 biosynthetic activity does not directly correlate with the phenotypes of SCD patients. The established cell-based assays in this study provide a powerful tool for the functional studies of UBIAD1 in a cellular milieu.
Collapse
Affiliation(s)
- Xuejie Chen
- Department of Biology, University of North Carolina at Chapel Hill, NC, USA
| | - Natsuko Furukawa
- Department of Bioscience and Engineering, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, Japan
| | - Da-Yun Jin
- Department of Biology, University of North Carolina at Chapel Hill, NC, USA
| | - Yizhou Liu
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia
| | - Darrel W Stafford
- Department of Biology, University of North Carolina at Chapel Hill, NC, USA
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia
| | - Yoshitomo Suhara
- Department of Bioscience and Engineering, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, Japan
| | - Jian-Ke Tie
- Department of Biology, University of North Carolina at Chapel Hill, NC, USA
| |
Collapse
|
9
|
Xie J, Li L. Functional study of SCCD pathogenic gene UBIAD1 (Review). Mol Med Rep 2021; 24:706. [PMID: 34368857 PMCID: PMC8365407 DOI: 10.3892/mmr.2021.12345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 06/29/2021] [Indexed: 12/22/2022] Open
Abstract
Schnyder's crystalline corneal dystrophy (SCCD) is a rare autosomal dominant genetic disorder that is characterized by progressive corneal opacity, owing to aberrant accumulation of cholesterol and phospholipids in the cornea. A number of SCCD affected families have been reported in the world since 1924, when it was first described. In 2007, the molecular basis of SCCD was demonstrated to be associated with a tumor suppressor, UbiA prenyltransferase domain-containing 1 (UBIAD1), which was isolated from the bladder mucosa and demonstrated to be involved in vitamin K2 and CoQ10 biosynthesis. This sterol triggers the binding of UBIAD1 to 3-hydroxy-3-methyl-glutaryl coenzyme A reductase (HMGCR) at endoplasmic reticulum (ER) membranes, which is regulated by an intracellular geranylgeranyl diphosphate (GGpp) molecule. The inability of SCCD-associated UBIAD1 to bind GGpp results in the consistent binding of UBIAD1 to HMGCR at ER membranes. This binding leads to HMGCRs being redundant. Therefore, they cannot be degraded through ER-associated degradation to synthesize abundant cholesterol in tissue cells. Excess corneal cholesterol accumulation thus leads to SCCD disease. After decades, the efforts of numerous ophthalmologists and scientists have helped clarify the molecular basis and pathogenesis of SCCD, which has guided the effective diagnosis and treatment of this genetic disorder. However, more studies need to be conducted to understand the pathogenesis of SCCD disease from a genetic basis by studying the defective gene, UBIAD1. Results would guide effective diagnosis and treatment of the inherited eye disease.
Collapse
Affiliation(s)
- Jumin Xie
- Medical School of Renal Disease Occurrence and Intervention, Hubei Polytechnic University, Huangshi, Hubei 435003, P.R. China
| | - Lingxing Li
- Department of Cardiovascular Medicine, Tai'an City Central Hospital, Tai'an, Shandong 271000, P.R. China
| |
Collapse
|
10
|
Schumacher MM, DeBose-Boyd RA. Posttranslational Regulation of HMG CoA Reductase, the Rate-Limiting Enzyme in Synthesis of Cholesterol. Annu Rev Biochem 2021; 90:659-679. [PMID: 34153214 DOI: 10.1146/annurev-biochem-081820-101010] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The polytopic, endoplasmic reticulum (ER) membrane protein 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase produces mevalonate, the key intermediate in the synthesis of cholesterol and many nonsterol isoprenoids including geranylgeranyl pyrophosphate (GGpp). Transcriptional, translational, and posttranslational feedback mechanisms converge on this reductase to ensure cells maintain a sufficient supply of essential nonsterol isoprenoids but avoid overaccumulation of cholesterol and other sterols. The focus of this review is mechanisms for the posttranslational regulation of HMG CoA reductase, which include sterol-accelerated ubiquitination and ER-associated degradation (ERAD) that is augmented by GGpp. We discuss how GGpp-induced ER-to-Golgi trafficking of the vitamin K2 synthetic enzyme UbiA prenyltransferase domain-containing protein-1 (UBIAD1) modulates HMG CoA reductase ERAD to balance the synthesis of sterol and nonsterol isoprenoids. We also summarize the characterization of genetically manipulated mice, which established that sterol-accelerated, UBIAD1-modulated ERAD plays a major role in regulation of HMG CoA reductase and cholesterol metabolism in vivo.
Collapse
Affiliation(s)
- Marc M Schumacher
- Department of Molecular Genetics, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA;
| | - Russell A DeBose-Boyd
- Department of Molecular Genetics, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA;
| |
Collapse
|
11
|
Pi Z, Liu J, Xiao H, Hu Z. L-3-n-butylphthalide promotes restoration after an experimental animal model of intracerebral hemorrhage. Int J Med Sci 2021; 18:2607-2614. [PMID: 34104092 PMCID: PMC8176182 DOI: 10.7150/ijms.60342] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 04/21/2021] [Indexed: 01/12/2023] Open
Abstract
Intracerebral hemorrhage (ICH) is a devastating type of stroke with high morbidity and mortality, and the effective therapies for ICH remain to be explored. L-3-n-butylphthalide (NBP) is widely used in the treatment of ischemic stroke. However, few studies evaluated the therapeutic effects of NBP on ICH. Therefore, the present study aims to evaluate the effects of NBP on ICH and its potential mechanism. The rats were randomly divided into sham-operated group, saline-treated (ICH + saline) group, and NBP-treated (ICH + NBP) group. The ICH model of SD rats induced by IV collagenase was established. The modified Garcia JH score was used to detect the neurological deficit in rats. Western Blot and immunohistochemistry analysis was applied to test the levels of UBIAD1 and caspase-3 expressions in the perihematomal region. The rates of apoptotic cells were detected by TUNEL staining. The results showed that NBP up-regulated the expression of UBIAD1, reduced the apoptotic cells in the perihematomal region, and improved the neurological deficit. Taken together, our study added some new evidence to the application of NBP in ICH treatment.
Collapse
Affiliation(s)
- Zhendong Pi
- Department of Neurology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jianyang Liu
- Department of Neurology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Han Xiao
- Department of Neurology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zhiping Hu
- Department of Neurology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| |
Collapse
|
12
|
Soh YQ, Kocaba V, Weiss JS, Jurkunas UV, Kinoshita S, Aldave AJ, Mehta JS. Corneal dystrophies. Nat Rev Dis Primers 2020; 6:46. [PMID: 32528047 DOI: 10.1038/s41572-020-0178-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/24/2020] [Indexed: 12/21/2022]
Abstract
Corneal dystrophies are broadly defined as inherited disorders that affect any layer of the cornea and are usually progressive, bilateral conditions that do not have systemic effects. The 2015 International Classification of Corneal Dystrophies classifies corneal dystrophies into four classes: epithelial and subepithelial dystrophies, epithelial-stromal TGFBI dystrophies, stromal dystrophies and endothelial dystrophies. Whereas some corneal dystrophies may result in few or mild symptoms and morbidity throughout a patient's lifetime, others may progress and eventually result in substantial visual and ocular disturbances that require medical or surgical intervention. Corneal transplantation, either with full-thickness or partial-thickness donor tissue, may be indicated for patients with advanced corneal dystrophies. Although corneal transplantation techniques have improved considerably over the past two decades, these surgeries are still associated with postoperative risks of disease recurrence, graft failure and other complications that may result in blindness. In addition, a global shortage of cadaveric corneal graft tissue critically limits accessibility to corneal transplantation in some parts of the world. Ongoing advances in gene therapy, regenerative therapy and cell augmentation therapy may eventually result in the development of alternative, novel treatments for corneal dystrophies, which may substantially improve the quality of life of patients with these disorders.
Collapse
Affiliation(s)
- Yu Qiang Soh
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore, Singapore.,Singapore National Eye Centre, Singapore, Singapore.,Ophthalmology Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore, Singapore.,Department of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Viridiana Kocaba
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore, Singapore.,Netherlands Institute for Innovative Ocular Surgery, Rotterdam, Netherlands
| | - Jayne S Weiss
- Department of Ophthalmology, Pathology and Pharmacology, Louisiana State University, School of Medicine, New Orleans, USA
| | - Ula V Jurkunas
- Cornea and Refractive Surgery Service, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, USA.,Schepens Eye Research Institute, Boston, Massachusetts, USA.,Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
| | - Shigeru Kinoshita
- Department of Frontier Medical Science and Technology for Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Anthony J Aldave
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Jodhbir S Mehta
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore, Singapore. .,Singapore National Eye Centre, Singapore, Singapore. .,Ophthalmology Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore, Singapore. .,Department of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore, Singapore.
| |
Collapse
|
13
|
Jun DJ, Schumacher MM, Hwang S, Kinch LN, Grishin NV, DeBose-Boyd RA. Schnyder corneal dystrophy-associated UBIAD1 is defective in MK-4 synthesis and resists autophagy-mediated degradation. J Lipid Res 2020; 61:746-757. [PMID: 32188638 PMCID: PMC7193952 DOI: 10.1194/jlr.ra119000551] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/21/2020] [Indexed: 12/15/2022] Open
Abstract
The autosomal dominant disorder Schnyder corneal dystrophy (SCD) is caused by mutations in UbiA prenyltransferase domain-containing protein-1 (UBIAD1), which uses geranylgeranyl pyrophosphate (GGpp) to synthesize the vitamin K2 subtype menaquinone-4 (MK-4). SCD is characterized by opacification of the cornea, owing to aberrant build-up of cholesterol in the tissue. We previously discovered that sterols stimulate association of UBIAD1 with ER-localized HMG-CoA reductase, which catalyzes a rate-limiting step in the synthesis of cholesterol and nonsterol isoprenoids, including GGpp. Binding to UBIAD1 inhibits sterol-accelerated ER-associated degradation (ERAD) of reductase and permits continued synthesis of GGpp in cholesterol-replete cells. GGpp disrupts UBIAD1-reductase binding and thereby allows for maximal ERAD of reductase as well as ER-to-Golgi translocation of UBIAD1. SCD-associated UBIAD1 is refractory to GGpp-mediated dissociation from reductase and remains sequestered in the ER to inhibit ERAD. Here, we report development of a biochemical assay for UBIAD1-mediated synthesis of MK-4 in isolated membranes and intact cells. Using this assay, we compared enzymatic activity of WT UBIAD1 with that of SCD-associated variants. Our studies revealed that SCD-associated UBIAD1 exhibited reduced MK-4 synthetic activity, which may result from its reduced affinity for GGpp. Sequestration in the ER protects SCD-associated UBIAD1 from autophagy and allows intracellular accumulation of the mutant protein, which amplifies the inhibitory effect on reductase ERAD. These findings have important implications not only for the understanding of SCD etiology but also for the efficacy of cholesterol-lowering statin therapy, which becomes limited, in part, because of UBIAD1-mediated inhibition of reductase ERAD.
Collapse
Affiliation(s)
- Dong-Jae Jun
- Departments of Molecular Genetics,University of Texas Southwestern Medical Center, Dallas, TX 75390-9046
| | - Marc M Schumacher
- Departments of Molecular Genetics,University of Texas Southwestern Medical Center, Dallas, TX 75390-9046
| | - Seonghwan Hwang
- Departments of Molecular Genetics,University of Texas Southwestern Medical Center, Dallas, TX 75390-9046
| | - Lisa N Kinch
- Biophysics,University of Texas Southwestern Medical Center, Dallas, TX 75390-9046
| | - Nick V Grishin
- Biophysics,University of Texas Southwestern Medical Center, Dallas, TX 75390-9046; Howard Hughes Medical Institute,University of Texas Southwestern Medical Center, Dallas, TX 75390-9046
| | - Russell A DeBose-Boyd
- Departments of Molecular Genetics,University of Texas Southwestern Medical Center, Dallas, TX 75390-9046. mailto:
| |
Collapse
|
14
|
Multimodal Imaging Features of Schnyder Corneal Dystrophy. J Ophthalmol 2020; 2020:6701816. [PMID: 32280528 PMCID: PMC7125492 DOI: 10.1155/2020/6701816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Accepted: 02/04/2020] [Indexed: 11/29/2022] Open
Abstract
Objective To describe the multimodal imaging of Schnyder corneal dystrophy. Methods Seven eyes of seven patients (5 female and 2 male patients) aged 52 to 92 years were included in this prospective observational study. Diagnosis of SCD was confirmed by histology after keratoplasty. In vivo multimodal imaging consisted of spectral domain-optical coherence tomography with cross sections, en face scans, corneal pachymetry, and epithelial mapping, and in vivo confocal microscopy was recorded. Ex vivo full-field optical coherence tomography scans of two corneal buttons were analyzed. The seven corneal buttons obtained during penetrating or deep anterior lamellar keratoplasty were processed for light microscopy. Results Slit-lamp examination showed central stromal opacities, arcus lipoides, and midperipheral haze. Corneal crystals were found in 2 out of 7 eyes. SD-OCT cross sections and en face scans showed diffuse hyperreflectivity of the anterior, mid, and posterior stroma with a maximum in the anterior stroma, hyporeflective stromal striae, and epithelial hyperreflectivity. Central corneal thickness ranged from 507 to 635 μm. IVCM revealed hyperreflective deposits in the epithelium and throughout the stroma, thin subepithelial nerves, and needle-shaped and rectangular crystals. Keratocyte nuclei were rare or undetectable. FF-OCT scans confirmed the presence of small round and needle-shaped hyperreflective deposits in the epithelium and stroma. Histology revealed vacuolization of the basal epithelial cells and empty interlamellar stromal vacuoles. Conclusion High-resolution multimodal imaging demonstrates the characteristic features of SCD which involve both the corneal epithelium and stroma, and it provides diagnosis confirmation even in eyes with no visible corneal crystals at slit-lamp examination.
Collapse
|
15
|
Jo Y, Kim SS, Garland K, Fuentes I, DiCarlo LM, Ellis JL, Fu X, Booth SL, Evers BM, DeBose-Boyd RA. Enhanced ER-associated degradation of HMG CoA reductase causes embryonic lethality associated with Ubiad1 deficiency. eLife 2020; 9:54841. [PMID: 32118581 PMCID: PMC7069719 DOI: 10.7554/elife.54841] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 03/02/2020] [Indexed: 12/15/2022] Open
Abstract
UbiA prenyltransferase domain-containing protein-1 (UBIAD1) synthesizes the vitamin K subtype menaquinone-4 (MK-4). Previous studies in cultured cells (Schumacher et al., 2015) revealed that UBIAD1 also inhibits endoplasmic reticulum (ER)-associated degradation (ERAD) of ubiquitinated HMG CoA reductase (HMGCR), the rate-limiting enzyme of the mevalonate pathway that produces cholesterol and essential nonsterol isoprenoids. Gene knockout studies were previously attempted to explore the function of UBIAD1 in mice; however, homozygous germ-line elimination of the Ubiad1 gene caused embryonic lethality. We now report that homozygous deletion of Ubiad1 is produced in knockin mice expressing ubiquitination/ERAD-resistant HMGCR. Thus, embryonic lethality of Ubiad1 deficiency results from depletion of mevalonate-derived products owing to enhanced ERAD of HMGCR rather than from reduced synthesis of MK-4. These findings provide genetic evidence for the significance of UBIAD1 in regulation of cholesterol synthesis and offer the opportunity in future studies for the discovery of new physiological roles of MK-4.
Collapse
Affiliation(s)
- Youngah Jo
- Department of Molecular Genetics, University of Texas Southwestern Medical, Dallas, United States
| | - Steven S Kim
- Department of Molecular Genetics, University of Texas Southwestern Medical, Dallas, United States
| | - Kristina Garland
- Department of Molecular Genetics, University of Texas Southwestern Medical, Dallas, United States
| | - Iris Fuentes
- Department of Molecular Genetics, University of Texas Southwestern Medical, Dallas, United States
| | - Lisa M DiCarlo
- Department of Molecular Genetics, University of Texas Southwestern Medical, Dallas, United States
| | - Jessie L Ellis
- Center at Dallas and Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Somerville, United States
| | - Xueyan Fu
- Center at Dallas and Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Somerville, United States
| | - Sarah L Booth
- Center at Dallas and Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Somerville, United States
| | - Bret M Evers
- Department of Pathology, University of Texas Southwestern Medical, Dallas, United States
| | - Russell A DeBose-Boyd
- Department of Molecular Genetics, University of Texas Southwestern Medical, Dallas, United States
| |
Collapse
|
16
|
Boral D, Rao VK, Ramasamy S. Archeal Di-O-geranylgeranyl Glyceryl Phosphate Synthase of a UbiA Superfamily Member Provides Insight into the Multiple Human Diseases. Protein Pept Lett 2019; 27:568-573. [PMID: 31814543 DOI: 10.2174/0929866526666191209143948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 10/11/2019] [Accepted: 10/29/2019] [Indexed: 11/22/2022]
Abstract
One of the unique characteristic features of the domain archaea, are the lipids that form the hydrophobic core of their cell membrane. These membrane lipids are characterized by distinctive isoprenoid biochemistry and the building blocks are two core lipid structures, sn-2,3- diphytanyl glycerol diether (archaeol) and sn-2,3-dibiphytanyl diglycerol tetraether (caldarchaeol). Archaeol has two phytanyl chains (C20) in a bilayer structure connected to the glycerol moiety by an ether bond. The enzyme involved in this bilayer formation is Di-O-Geranylgeranyl Glyceryl Phosphate Synthase (DGGGPS), which is a member of a very versatile superfamily of enzymes known as UbiA superfamily. Multiple sequence analysis of the typical members of the UbiA superfamily indicates that the majority of conserved residues are located around the central cavity of these enzymes. Interestingly few of these conserved residues in the human homologs are centrally implicated in several human diseases, on basis of the major mutations reported against these diseases in the earlier clinical studies. It remains to be investigated about the role of these conserved residues in the biochemistry of these enzymes. The binding and active site of these enzymes found to be similar architecture but have different substrate affinities ranging from aromatic to linear compounds. So further investigation of UbiA superfamily may be translated to novel therapeutic and diagnostic application of these proteins in human disease management.
Collapse
Affiliation(s)
- Debjyoti Boral
- Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune-411008, India
| | | | - Sureshkumar Ramasamy
- Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune-411008, India
| |
Collapse
|
17
|
Chen L, Chen XW, Huang X, Song BL, Wang Y, Wang Y. Regulation of glucose and lipid metabolism in health and disease. SCIENCE CHINA-LIFE SCIENCES 2019; 62:1420-1458. [PMID: 31686320 DOI: 10.1007/s11427-019-1563-3] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 10/15/2019] [Indexed: 02/08/2023]
Abstract
Glucose and fatty acids are the major sources of energy for human body. Cholesterol, the most abundant sterol in mammals, is a key component of cell membranes although it does not generate ATP. The metabolisms of glucose, fatty acids and cholesterol are often intertwined and regulated. For example, glucose can be converted to fatty acids and cholesterol through de novo lipid biosynthesis pathways. Excessive lipids are secreted in lipoproteins or stored in lipid droplets. The metabolites of glucose and lipids are dynamically transported intercellularly and intracellularly, and then converted to other molecules in specific compartments. The disorders of glucose and lipid metabolism result in severe diseases including cardiovascular disease, diabetes and fatty liver. This review summarizes the major metabolic aspects of glucose and lipid, and their regulations in the context of physiology and diseases.
Collapse
Affiliation(s)
- Ligong Chen
- School of Pharmaceutical Sciences, Beijing Advanced Innovation Center for Structural Biology, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Tsinghua University, Beijing, 100084, China.
| | - Xiao-Wei Chen
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China.
| | - Xun Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Bao-Liang Song
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
| | - Yan Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
| | - Yiguo Wang
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
| |
Collapse
|
18
|
Granadeiro L, Dirks RP, Ortiz-Delgado JB, Gavaia PJ, Sarasquete C, Laizé V, Cancela ML, Fernández I. Warfarin-exposed zebrafish embryos resembles human warfarin embryopathy in a dose and developmental-time dependent manner - From molecular mechanisms to environmental concerns. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 181:559-571. [PMID: 31238190 DOI: 10.1016/j.ecoenv.2019.06.042] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/13/2019] [Accepted: 06/14/2019] [Indexed: 06/09/2023]
Abstract
Warfarin is the most worldwide used anticoagulant drug and rodenticide. Since it crosses placental barrier it can induce warfarin embryopathy (WE), a fetal mortality in neonates characterized by skeletal deformities in addition to brain hemorrhages. Although the effects of warfarin exposure in aquatic off target species were already described, the particular molecular toxicological mechanisms during early development are still unclear. Here, we used zebrafish (Danio rerio) to describe and compare the developmental effects of warfarin exposure (0, 15.13, 75.68 and 378.43 mM) on two distinct early developmental phases (embryos and eleuthero-embryos). Although exposure to both developmental phases induced fish mortality, only embryos exposed to the highest warfarin level exhibited features mimicking mammalian WE, e.g. high mortality, higher incidence of hemorrhages and altered skeletal development, among other effects. To gain insights into the toxic mechanisms underlying warfarin exposure, the transcriptome of embryos exposed to warfarin was explored through RNA-Seq and compared to that of control embryos. 766 differentially expressed (564 up- and 202 down-regulated) genes were identified. Gene Ontology analysis revealed particular cellular components (cytoplasm, extracellular matrix, lysosome and vacuole), biological processes (mainly amino acid and lipid metabolism and response to stimulus) and pathways (oxidative stress response and apoptosis signaling pathways) being significantly overrepresented in zebrafish embryos upon warfarin exposure. Protein-protein interaction further evidenced an altered redox system, blood coagulation and vasculogenesis, visual phototransduction and collagen formation upon warfarin exposure. The present study not only describes for the first time the WE in zebrafish, it provides new insights for a better risk assessment, and highlights the need for programming the rat eradication actions outside the fish spawning season to avoid an impact on off target fish community. The urge for the development of more species-specific anticoagulants for rodent pest control is also highlighted.
Collapse
Affiliation(s)
- Luis Granadeiro
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Ron P Dirks
- ZF-screens B.V. J.H. Oortweg 19, 2333, CH Leiden, the Netherlands
| | - Juan B Ortiz-Delgado
- Instituto de Ciencias Marinas de Andalucía-ICMAN/CSIC, Campus Universitario Río San Pedro, Apdo. Oficial, 11510, Puerto Real, Cádiz, Spain
| | - Paulo J Gavaia
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Departamento de Ciências Biomédicas e Medicina (DCBM), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Carmen Sarasquete
- Instituto de Ciencias Marinas de Andalucía-ICMAN/CSIC, Campus Universitario Río San Pedro, Apdo. Oficial, 11510, Puerto Real, Cádiz, Spain
| | - Vincent Laizé
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - M Leonor Cancela
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Departamento de Ciências Biomédicas e Medicina (DCBM), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Algarve Biomedical Center (ABC) and Centre for Biomedical Research (CBMR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Ignacio Fernández
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Center for Aquaculture Research, Agrarian Technological Institute of Castile and Leon, Ctra. Arévalo, S/n. 40196 Zamarramala, Segovia, Spain.
| |
Collapse
|
19
|
Jiang SY, Tang JJ, Xiao X, Qi W, Wu S, Jiang C, Hong J, Xu J, Song BL, Luo J. Schnyder corneal dystrophy-associated UBIAD1 mutations cause corneal cholesterol accumulation by stabilizing HMG-CoA reductase. PLoS Genet 2019; 15:e1008289. [PMID: 31323021 PMCID: PMC6668851 DOI: 10.1371/journal.pgen.1008289] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 07/31/2019] [Accepted: 07/04/2019] [Indexed: 11/29/2022] Open
Abstract
Schnyder corneal dystrophy (SCD) is a rare genetic eye disease characterized by corneal opacification resulted from deposition of excess free cholesterol. UbiA prenyltransferase domain-containing protein-1 (UBIAD1) is an enzyme catalyzing biosynthesis of coenzyme Q10 and vitamin K2. More than 20 UBIAD1 mutations have been found to associate with human SCD. How these mutants contribute to SCD development is not fully understood. Here, we identified HMGCR as a binding partner of UBIAD1 using mass spectrometry. In contrast to the Golgi localization of wild-type UBIAD1, SCD-associated mutants mainly resided in the endoplasmic reticulum (ER) and competed with Insig-1 for HMGCR binding, thereby preventing HMGCR from degradation and increasing cholesterol biosynthesis. The heterozygous Ubiad1 G184R knock-in (Ubiad1G184R/+) mice expressed elevated levels of HMGCR protein in various tissues. The aged Ubiad1G184R/+ mice exhibited corneal opacification and free cholesterol accumulation, phenocopying clinical manifestations of SCD patients. In summary, these results demonstrate that SCD-associated mutations of UBIAD1 impair its ER-to-Golgi transportation and enhance its interaction with HMGCR. The stabilization of HMGCR by UBIAD1 increases cholesterol biosynthesis and eventually causes cholesterol accumulation in the cornea. Schnyder corneal dystrophy (SCD) is a rare genetic eye disease caused by deposition of free cholesterol in the cornea. It is closely correlated with mutations in the UbiA prenyltransferase domain-containing protein-1 (UBIAD1) gene, which encodes an enzyme catalyzing biosynthesis of coenzyme Q10 and vitamin K2. The underlying mechanism by which UBIAD1 mutations result in SCD development is unclear. Here, we report that SCD-associated mutations trap UBIAD1 in the ER and block Insig-1 mediated HMGCR degradation. We also generated a heterozygous mouse model (Ubiad1G184R/+) that mimics human SCD. We conclude that SCD-associated UBIAD1 mutations decrease HMGCR degradation and subsequently increase cholesterol biosynthesis in the cornea.
Collapse
Affiliation(s)
- Shi-You Jiang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jing-Jie Tang
- The State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xu Xiao
- The State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Wei Qi
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Suqian Wu
- Department of Ophthalmology and Visual Science, Eye Institute, Eye and ENT Hospital, Shanghai Medical College of Fudan University, NHC Key Laboratory of myopia (Fudan University), Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Chao Jiang
- Department of Ophthalmology and Visual Science, Eye Institute, Eye and ENT Hospital, Shanghai Medical College of Fudan University, NHC Key Laboratory of myopia (Fudan University), Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Jiaxu Hong
- Department of Ophthalmology and Visual Science, Eye Institute, Eye and ENT Hospital, Shanghai Medical College of Fudan University, NHC Key Laboratory of myopia (Fudan University), Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Jianjiang Xu
- Department of Ophthalmology and Visual Science, Eye Institute, Eye and ENT Hospital, Shanghai Medical College of Fudan University, NHC Key Laboratory of myopia (Fudan University), Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
- * E-mail: (JX); (BLS); (JL)
| | - Bao-Liang Song
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
- Shenzhen Institute of Wuhan University, Shenzhen, China
- * E-mail: (JX); (BLS); (JL)
| | - Jie Luo
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
- * E-mail: (JX); (BLS); (JL)
| |
Collapse
|
20
|
Clinical and genetic update of corneal dystrophies. Exp Eye Res 2019; 186:107715. [PMID: 31301286 DOI: 10.1016/j.exer.2019.107715] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 06/06/2019] [Accepted: 06/27/2019] [Indexed: 11/23/2022]
Abstract
The International Committee for Classification of Corneal Dystrophies (IC3D) distinguishes between 22 distinct forms of corneal dystrophy which are predominantly autosomal dominant, although autosomal recessive and X-chromosomal dominant patterns do exist. Before any genetic examination, there should be documentation of a detailed corneal exam of as many affected and unaffected family members as possible, because detailed phenotypic description is essential for accurate diagnosis. Corneal documentation should be performed in direct and indirect illumination at the slit lamp with the pharmacologically dilated pupil. For the majority of the corneal dystrophies, a phenotype-genotype correlation has not been demonstrated. However, for the dystrophies associated with mutations in the transforming growth factor, ß-induced gene (TGFBI) a general phenotype-genotype correlation is evident. The discovery of collagen, type XVII, alpha 1 mutation (COL17A1), causative in the called epithelial recurrent erosion dystrophy (ERED) was a very important step in the accurate diagnosis of corneal dystrophies. This led to the subsequent discovery that the entity previously called 10q Thiel-Behnke corneal dystrophy, was in reality actually COL17A1 ERED, and not Thiel-Behnke corneal dystrophy. In addition to the phenotypic landmarks, we describe the current genotype of the individual corneal dystrophies. Differential diagnosis can be aided by information on histopathology, optical coherence tomography (OCT), and confocal microscopy.
Collapse
|
21
|
Harshman SG, Shea MK, Fu X, Grusak MA, Smith D, Lamon-Fava S, Kuliopulos A, Greenberg A, Booth SL. Atorvastatin Decreases Renal Menaquinone-4 Formation in C57BL/6 Male Mice. J Nutr 2019; 149:416-421. [PMID: 30753659 PMCID: PMC6398385 DOI: 10.1093/jn/nxy290] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 07/30/2018] [Accepted: 10/25/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Menaquinone-4 (MK4), a vitamin K metabolite, is converted from phylloquinone through a process that requires intermediates of endogenous cholesterol production. Recent evidence suggests that MK4 is involved in kidney function. OBJECTIVE The purpose of this study was to determine the effect of atorvastatin treatment on MK4 formation in young and old male mice. METHODS C57BL/6 male mice (4-mo-old and 20-mo-old) were randomly assigned to either a diet containing 300 mg atorvastatin/kg with 3 mg phylloquinone/kg or a control diet containing 3 mg phylloquinone/kg for 8 wk. During week 8, all mice received deuterium-labeled phylloquinone in the diet. Labeled and unlabeled phylloquinone and MK4 in liver, kidney, brain, and intestine were measured by atmospheric pressure chemical ionization LC/MS. 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase gene expression was quantified by reverse transcriptase-PCR. Tissue MK4 and phylloquinone concentrations were compared between atorvastatin treatment groups with use of general linear models. RESULTS There was no age-treatment interaction on MK4 tissue concentrations. In atorvastatin-treated mice, total MK4 and percentage of deuterium-labeled MK4 in kidney were both approximately 45% lower compared to values in mice not given atorvastatin (all P < 0.05). MK4 concentrations did not differ between groups in any other tissue measured. CONCLUSION In male mice, atorvastatin reduced endogenous MK4 formation in the kidney, but not other organs. These observations are consistent with our hypothesis that cholesterol metabolism is involved in the generation of MK4. Further research is needed to understand potential regulatory mechanisms and the unique functions of MK4 in the kidney.
Collapse
Affiliation(s)
| | - M Kyla Shea
- Jean Mayer USDA Human Nutrition Research Center on Aging
| | - Xueyan Fu
- Jean Mayer USDA Human Nutrition Research Center on Aging
| | - Michael A Grusak
- USDA/ARS Red River Valley Agricultural Research Center, Fargo, ND
| | - Donald Smith
- Jean Mayer USDA Human Nutrition Research Center on Aging
| | | | - Athan Kuliopulos
- Sackler School of Biomedical Sciences, Tufts University, Boston, MA
| | | | - Sarah L Booth
- Jean Mayer USDA Human Nutrition Research Center on Aging,Address correspondence to SLB (e-mail: )
| |
Collapse
|
22
|
Jo Y, Hamilton JS, Hwang S, Garland K, Smith GA, Su S, Fuentes I, Neelam S, Thompson BM, McDonald JG, DeBose-Boyd RA. Schnyder corneal dystrophy-associated UBIAD1 inhibits ER-associated degradation of HMG CoA reductase in mice. eLife 2019; 8:44396. [PMID: 30785396 PMCID: PMC6402834 DOI: 10.7554/elife.44396] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 02/19/2019] [Indexed: 12/14/2022] Open
Abstract
Autosomal-dominant Schnyder corneal dystrophy (SCD) is characterized by corneal opacification owing to overaccumulation of cholesterol. SCD is caused by mutations in UBIAD1, which utilizes geranylgeranyl pyrophosphate (GGpp) to synthesize vitamin K2. Using cultured cells, we previously showed that sterols trigger binding of UBIAD1 to the cholesterol biosynthetic enzyme HMG CoA reductase (HMGCR), thereby inhibiting its endoplasmic reticulum (ER)-associated degradation (ERAD) (Schumacher et al. 2015). GGpp triggers release of UBIAD1 from HMGCR, allowing maximal ERAD and ER-to-Golgi transport of UBIAD1. SCD-associated UBIAD1 resists GGpp-induced release and is sequestered in ER to inhibit ERAD. We now report knockin mice expressing SCD-associated UBIAD1 accumulate HMGCR in several tissues resulting from ER sequestration of mutant UBIAD1 and inhibition of HMGCR ERAD. Corneas from aged knockin mice exhibit signs of opacification and sterol overaccumulation. These results establish the physiological significance of UBIAD1 in cholesterol homeostasis and indicate inhibition of HMGCR ERAD contributes to SCD pathogenesis.
Collapse
Affiliation(s)
- Youngah Jo
- Departments of Molecular Genetics, Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, United States
| | - Jason S Hamilton
- Departments of Molecular Genetics, Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, United States
| | - Seonghwan Hwang
- Departments of Molecular Genetics, Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, United States
| | - Kristina Garland
- Departments of Molecular Genetics, Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, United States
| | - Gennipher A Smith
- Departments of Molecular Genetics, Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, United States
| | - Shan Su
- Departments of Molecular Genetics, Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, United States
| | - Iris Fuentes
- Departments of Molecular Genetics, Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, United States
| | - Sudha Neelam
- Department of Ophthalmology, Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, United States
| | - Bonne M Thompson
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, United States
| | - Jeffrey G McDonald
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, United States
| | - Russell A DeBose-Boyd
- Departments of Molecular Genetics, Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, United States
| |
Collapse
|
23
|
Xu Z, Duan F, Lu H, Abdulkadhim Dragh M, Xia Y, Liang H, Hong L. UBIAD1 suppresses the proliferation of bladder carcinoma cells by regulating H-Ras intracellular trafficking via interaction with the C-terminal domain of H-Ras. Cell Death Dis 2018; 9:1170. [PMID: 30518913 PMCID: PMC6281600 DOI: 10.1038/s41419-018-1215-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 10/28/2018] [Accepted: 10/30/2018] [Indexed: 12/13/2022]
Abstract
UbiA prenyltransferase domain-containing protein 1 (UBIAD1) plays a key role in biosynthesis of vitamin K2 and coenzyme Q10 using geranylgeranyl diphosphate (GGPP). However, the mechanism by which UBIAD1 participates in tumorigenesis remains unknown. This study show that UBIAD1 interacts with H-Ras, retains H-Ras in the Golgi apparatus, prevents H-Ras trafficking from the Golgi apparatus to the plasma membrane, blocks the aberrant activation of Ras/MAPK signaling, and inhibits the proliferation of bladder cancer cells. In addition, GGPP was required to maintain the function of UBIAD1 in regulating the Ras/ERK signaling pathway. A Drosophila model was employed to confirm the function of UBIAD1/HEIX in vivo. The activation of Ras/ERK signaling at the plasma membrane induced melanotic masses in Drosophila larvae. Our study suggests that UBIAD1 serves as a tumor suppressor in cancer and tentatively reveals the underlying mechanism of melanotic mass formation in Drosophila.
Collapse
Affiliation(s)
- Zhiliang Xu
- Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Fengsen Duan
- Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Huiai Lu
- Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Maytham Abdulkadhim Dragh
- Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Yanzhi Xia
- Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Huageng Liang
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Ling Hong
- Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China.
| |
Collapse
|
24
|
Yan B, Wang J. UBIAD1 expression is associated with cardiac hypertrophy in spontaneously hypertensive rats. Mol Med Rep 2018; 19:651-659. [PMID: 30483777 DOI: 10.3892/mmr.2018.9693] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 10/05/2018] [Indexed: 11/06/2022] Open
Abstract
The present study investigated the potential role of UbiA prenyltransferase domain-containing 1 (UBIAD1) in the pathogenesis of hypertensive cardiac hypertrophy. Spontaneously hypertensive rats (SHRs) and Wistar‑Kyoto (WKY) rats at 8, 16 and 28 weeks of age were used. Blood pressure was measured using a non‑invasive tail cut‑off system. Cardiac functional index was assessed by arterial catheterization. Myocardial structure and cell apoptosis were evaluated by hematoxylin and eosin staining, and terminal deoxynucleotidyl‑transferase‑mediated dUTP nick end labeling assays, respectively. Myocardial expression of UBIAD1, coenzyme Q10 (CoQ10), endothelial nitric oxide synthase (eNOS) and atrial natriuretic peptide were evaluated by immunohistochemistry, western blotting and reverse transcription‑quantitative polymerase chain reaction. Circulating and myocardial expression of nitric oxide (NO) were measured using the Griess method. SHRs exhibited increased blood pressure and cardiomyocyte apoptosis, as well as cardiac hypertrophy, compared with age‑matched WKY rats. Myocardial expression of UBIAD1 was significantly decreased in SHRs in an age‑dependent manner. Similarly, myocardial CoQ10 and eNOS expression were significantly reduced in SHR compared to age‑matched WKY rats, and these expression levels additionally decreased further with aging. Serum and myocardial NO expression was additionally decreased in SHRs. Decreased UBIAD1 expression in SHR hearts was associated with decreased levels of CoQ10, eNOS and NO. Given the well‑established role of UBIAD1 in the regulation of NO signaling, reduced expression of UBIAD1 in SHR hearts potentially contributed to the pathogenesis of hypertensive cardiac hypertrophy. Therefore, UBIAD1 may represent a potential therapeutic target for clinical treatment of hypertensive cardiac hypertrophy.
Collapse
Affiliation(s)
- Bingju Yan
- Department of Cardiology, First Hospital of Jinzhou Medical University, Jinzhou, Liaoning 121000, P.R. China
| | - Jun Wang
- Department of General Surgery, First Hospital of Jinzhou Medical University, Jinzhou, Liaoning 121000, P.R. China
| |
Collapse
|
25
|
Gonzalvez M, Ho Wang Yin G, Gascon P, Denis D, Hoffart L. Clinical and para-clinical description of a novel mutation for Schnyder dystrophy in a French family. J Fr Ophtalmol 2018; 41:920-925. [PMID: 30446344 DOI: 10.1016/j.jfo.2018.03.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 03/21/2018] [Accepted: 03/22/2018] [Indexed: 11/30/2022]
Abstract
INTRODUCTION The objective of this article is to describe the evolution of Schnyder dystrophy in 3 related patients of different ages and to highlight the discovery of a new mutation unidentified until now. CASE REPORT We present a series of 3 cases, all first-degree relatives with no suggestion of consanguinity, of different ages (30, 40 and 59 years) and two distinct generations (mother and children). Slit lamp examination revealed the same lesions in our three patients: an early-onset corneal arcus senilis, central corneal deposits, and a gray stromal haze in the two oldest subjects. The older the patient, the more numerous and dense were these lesions. The various anterior segment OCTs showed an increase in the number of hyperreflective opacities in the anterior stroma and, in the older subject, the appearance of many posterior shadows. Monitoring of pachymetry by Pentacam® showed progressive age-related thickening. All three patients had dyslipidemia treated with statins or diet alone. In our case we proposed treatment only to subject A because of the significant impact on her visual acuity. DISCUSSION Numerous clinical, para-clinical and genetic descriptions of this disease are found in the literature. Schnyder dystrophy is rare but not unheard of and may be discovered fortuitously or in the setting of decreased visual acuity. Genetic analysis of our family revealed a mutation of the UBIAD1 gene not described in the literature. UBIAD1 encodes the protein domain-containing UbiA prenyltransferase 1 which converts vitamin K1 into K2 and is involved in the cholesterol synthesis pathway. In the case of a mutation, it is no longer functional, leading to the accumulation of cholesterol crystals. Given the clinical context and the presence of this variant of the reference sequence in all relatives, its pathogenesis is strongly suspected in our family. The originality of our article is to present the progression of the same pathology in 3 patients with the same mutation at different ages and degrees of severity. This notion of progressive worsening and the need to treat late in the majority of cases are found in literature. CONCLUSION The discovery of a new variant within the UBAID1 gene suggests its pathogenesis in view of the clinical features available to us. The dystrophy is initially asymptomatic before the high number of deposits becomes disabling.
Collapse
Affiliation(s)
- M Gonzalvez
- Aix-Marseille université, 13284 Marseille, France; Service d'ophtalmologie, hôpital de la Timone, AP-HM, 264, rue Saint-Pierre, 13385 Marseille, France.
| | - G Ho Wang Yin
- Aix-Marseille université, 13284 Marseille, France; Service d'ophtalmologie, hôpital de la Timone, AP-HM, 264, rue Saint-Pierre, 13385 Marseille, France
| | - P Gascon
- Aix-Marseille université, 13284 Marseille, France; Service d'ophtalmologie, hôpital de la Timone, AP-HM, 264, rue Saint-Pierre, 13385 Marseille, France
| | - D Denis
- Aix-Marseille université, 13284 Marseille, France; Service d'ophtalmologie, hôpital de la Timone, AP-HM, 264, rue Saint-Pierre, 13385 Marseille, France
| | - L Hoffart
- Aix-Marseille université, 13284 Marseille, France; Service d'ophtalmologie, hôpital de la Timone, AP-HM, 264, rue Saint-Pierre, 13385 Marseille, France
| |
Collapse
|
26
|
Weiss JS, Møller HU, Lisch W. The Corneal Dystrophies-Does the Literature Clarify or Confuse? Am J Ophthalmol 2018; 195:xv-xvii. [PMID: 30217469 DOI: 10.1016/j.ajo.2018.07.047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 07/27/2018] [Accepted: 07/30/2018] [Indexed: 11/16/2022]
Affiliation(s)
- Jayne S Weiss
- Departments of Ophthalmology, Pathology and Pharmacology, Louisiana State University School of Medicine, New Orleans, Louisiana, USA.
| | - Hans Ulrik Møller
- Department of Pediatric Ophthalmology, Viborg Hospital and Århus University Hospital, Århus, Denmark
| | - Walter Lisch
- Department of Ophthalmology, Johannes Gutenberg University Mainz, Mainz, Germany
| |
Collapse
|
27
|
Sarosiak A, Udziela M, Ścieżyńska A, Oziębło D, Wawrzynowska A, Szaflik JP, Ołdak M. Clinical diversity in patients with Schnyder corneal dystrophy-a novel and known UBIAD1 pathogenic variants. Graefes Arch Clin Exp Ophthalmol 2018; 256:2127-2134. [PMID: 30084067 PMCID: PMC6208719 DOI: 10.1007/s00417-018-4075-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 06/29/2018] [Accepted: 07/23/2018] [Indexed: 12/21/2022] Open
Abstract
PURPOSE Schnyder corneal dystrophy (SCD) is a rare inherited disease that leads to gradual vision loss by the deposition of lipids in the corneal stroma. The aim of this study is to report a novel pathogenic variant in the UBIAD1 gene and present clinical and molecular findings in Polish patients with SCD. METHODS Individuals (n = 37) originating from four Polish SCD families were subjected for a complete ophthalmological check-up and genetic testing. Corneal changes were visualized by slit-lamp examination, anterior segment optical coherent tomography (AS-OCT), and in vivo confocal microscopy (IVCM). RESULTS In a proband with primarily mild SCD that progressed rapidly at the end of the fifth decade of life, a novel missense pathogenic variant in UBIAD1 (p.Thr120Arg) was identified. The other studied SCD family represents the second family reported worldwide with the UBIAD1 p.Asp112Asn variant. SCD in the remaining two families resulted from a frequently identified p.Asn102Ser pathogenic variant. All affected subjects presented a crystalline form of SCD. The severity of corneal changes was age-dependent, and their morphology and localization are described in detail. CONCLUSION The novel p.Thr120Arg is the fourth SCD-causing variant lying within the FARM motif of the UBIAD1 protein, which underlines a high importance of this motif for SCD pathogenesis. The current study provides independent evidence for the pathogenic potential of UBIAD1 p.Asp112Asn and new information useful for clinicians.
Collapse
Affiliation(s)
- Anna Sarosiak
- Department of Histology and Embryology, Center of Biostructure Research, Medical University of Warsaw, T. Chałubińskiego 5, 02-004, Warsaw, Poland
- Postgraduate School of Molecular Medicine, Medical University of Warsaw, Warsaw, Poland
| | - Monika Udziela
- Department of Ophthalmology, Medical University of Warsaw, Warsaw, Poland
| | - Aneta Ścieżyńska
- Department of Histology and Embryology, Center of Biostructure Research, Medical University of Warsaw, T. Chałubińskiego 5, 02-004, Warsaw, Poland
| | - Dominika Oziębło
- Department of Histology and Embryology, Center of Biostructure Research, Medical University of Warsaw, T. Chałubińskiego 5, 02-004, Warsaw, Poland
- Postgraduate School of Molecular Medicine, Medical University of Warsaw, Warsaw, Poland
| | - Anna Wawrzynowska
- Department of Histology and Embryology, Center of Biostructure Research, Medical University of Warsaw, T. Chałubińskiego 5, 02-004, Warsaw, Poland
| | - Jacek P Szaflik
- Department of Ophthalmology, Medical University of Warsaw, Warsaw, Poland
| | - Monika Ołdak
- Department of Histology and Embryology, Center of Biostructure Research, Medical University of Warsaw, T. Chałubińskiego 5, 02-004, Warsaw, Poland.
| |
Collapse
|
28
|
Evans CJ, Dudakova L, Skalicka P, Mahelkova G, Horinek A, Hardcastle AJ, Tuft SJ, Liskova P. Schnyder corneal dystrophy and associated phenotypes caused by novel and recurrent mutations in the UBIAD1 gene. BMC Ophthalmol 2018; 18:250. [PMID: 30223810 PMCID: PMC6142341 DOI: 10.1186/s12886-018-0918-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 09/06/2018] [Indexed: 01/03/2023] Open
Abstract
Background The purpose of this study was to identify the genetic cause and describe the clinical phenotype of Schnyder corneal dystrophy (SCD) in six unrelated probands. Methods We identified two white Czech, two white British and two South Asian families with a clinical diagnosis of SCD. Ophthalmic assessment included spectral domain optical coherence tomography (SD-OCT) of one individual with advanced disease, and SD-OCT and confocal microscopy of a child with early stages of disease. UBIAD1 coding exons were amplified and Sanger sequenced in each proband. A fasting serum lipid profile was measured in three probands. Paternity testing was performed in one family. Results A novel heterozygous c.527G>A; p.(Gly176Glu) mutation in UBIAD1 was identified in one Czech proband. In the second Czech proband, aged 6 years when first examined, a previously described de novo heterozygous c.289G>A; p.(Ala97Thr) mutation was found. Two probands of South Asian descent carried a known c.305G>A; p.(Asn102Ser) mutation in the heterozygous state. Previously reported heterozygous c.361C>T; p.(Leu121Phe) and c.308C>T; p.(Thr103Ile) mutations were found in two white British families. Although crystalline deposits were present in all probands the affected area was small in some individuals. Corneal arcus and stromal haze were the most prominent phenotypical feature in two probands. In the Czech probands, SD-OCT confirmed accumulation of reflective material in the anterior stroma. Crystalline deposits were visualized by confocal microscopy. Mild dyslipidemia was found in all three individuals tested. Conclusion Although de novo occurrence of mutations in UBIAD1 is extremely rare, SCD should be considered in the differential diagnosis of bilateral corneal haze and/or crystal deposition, especially in children.
Collapse
Affiliation(s)
| | - Lubica Dudakova
- Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, 128 08, Prague 2, Czech Republic
| | - Pavlina Skalicka
- Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, 128 08, Prague 2, Czech Republic.,Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Gabriela Mahelkova
- Department of Ophthalmology, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic
| | - Ales Horinek
- 3rd Department of Medicine, Department of Endocrinology and Metabolism, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.,Institute of Biology and Human Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | | | | | - Petra Liskova
- Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, 128 08, Prague 2, Czech Republic. .,Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
| |
Collapse
|
29
|
Dong F, Jin X, Boettler MA, Sciulli H, Abu-Asab M, Del Greco C, Wang S, Hu YC, Campos MM, Jackson SN, Muller L, Woods AS, Combs CA, Zhang J, Nickerson ML, Kruth HS, Weiss JS, Kao WW. A Mouse Model of Schnyder Corneal Dystrophy with the N100S Point Mutation. Sci Rep 2018; 8:10219. [PMID: 29977031 PMCID: PMC6033878 DOI: 10.1038/s41598-018-28545-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 06/18/2018] [Indexed: 11/09/2022] Open
Abstract
Schnyder corneal dystrophy (SCD) is a rare autosomal dominant disease in humans, characterized by abnormal deposition of cholesterol and phospholipids in cornea caused by mutations in the UbiA prenyltransferase domain containing 1 (UBIAD1) gene. In this study, we generated a mouse line carrying Ubiad1 N100S point mutation using the CRISPR/Cas9 technique to investigate the pathogenesis of SCD. In vivo confocal microscopy revealed hyper-reflective dot-like deposits in the anterior cornea in heterozygotes and homozygotes. No significant change was found in corneal epithelial barrier function or wound healing. Electron microscopy revealed abnormal mitochondrial morphology in corneal epithelial, stromal, and endothelial cells. Mitochondrial DNA copy number assay showed 1.27 ± 0.07 fold change in homozygotes versus 0.98 ± 0.05 variation in wild type mice (P < 0.05). Lipidomic analysis indicated abnormal metabolism of glycerophosphoglycerols, a lipid class found in mitochondria. Four (34:1, 34:2, 36:2, and 44:8) of the 11 glycerophosphoglycerols species identified by mass spectrometry showed a significant increase in homozygous corneas compared with heterozygous and wild-type mouse corneas. Unexpectedly, we did not find a difference in the corneal cholesterol level between different genotypes by filipin staining or lipidomic analysis. The Ubiad1N100S mouse provides a promising animal model of SCD revealing that mitochondrial dysfunction is a prominent component of the disease. The different phenotype in human and mouse may due to difference in cholesterol metabolism between species.
Collapse
Affiliation(s)
- Fei Dong
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA
| | - Xueting Jin
- Laboratory of Experimental Atherosclerosis, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | | | - Harrison Sciulli
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA
| | - Mones Abu-Asab
- Histopathology Facility, National Eye Institute, NIH, Bethesda, MD, USA
| | | | - Shurong Wang
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA.,Ophthalmology, the Second Hospital of Jilin University, Changchun, Jilin, China
| | - Yueh-Chiang Hu
- Transgenic Animal and Genome Editing Core, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Maria M Campos
- Histopathology Facility, National Eye Institute, NIH, Bethesda, MD, USA
| | - Shelley N Jackson
- Structural Biology Core, National Institute of Drug Abuse, NIH, Baltimore, MD, USA
| | - Ludovic Muller
- Structural Biology Core, National Institute of Drug Abuse, NIH, Baltimore, MD, USA
| | - Amina S Woods
- Structural Biology Core, National Institute of Drug Abuse, NIH, Baltimore, MD, USA
| | - Christian A Combs
- Light Microscopy Core Facility, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Jianhua Zhang
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA
| | - Michael L Nickerson
- Laboratory of Translational Genomics, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Howard S Kruth
- Laboratory of Experimental Atherosclerosis, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Jayne S Weiss
- Department of Ophthalmology, Pathology and Pharmacology, Louisiana State University School of Medicine, Louisiana State University Eye Center, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Winston W Kao
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA.
| |
Collapse
|
30
|
Abstract
Vitamin K (VK) is an essential cofactor for the post-translational conversion of peptide-bound glutamate to γ-carboxyglutamate. The resultant vitamin K-dependent proteins are known or postulated to possess a variety of biological functions, chiefly in the maintenance of hemostasis. The vitamin K cycle is a cellular pathway that drives γ-carboxylation and recycling of VK via γ-carboxyglutamyl carboxylase (GGCX) and vitamin K epoxide reductase (VKOR), respectively. In this review, we show how novel molecular biological approaches are providing new insights into the pathophysiological mechanisms caused by rare mutations of both GGCX and VKOR. We also discuss how other protein regulators influence the intermediary metabolism of VK, first through intestinal absorption and second through a pathway that converts some dietary phylloquinone to menadione, which is prenylated to menaquinone-4 (MK-4) in target tissues by UBIAD1. The contribution of MK-4 synthesis to VK functions is yet to be revealed.
Collapse
Affiliation(s)
- Martin J Shearer
- Centre for Haemostasis and Thrombosis, Guy's and St Thomas' NHS Foundation Trust, London SE1 7EH, United Kingdom;
| | - Toshio Okano
- Department of Hygienic Sciences, Kobe Pharmaceutical University, Kobe 658-8558 Japan;
| |
Collapse
|
31
|
Long-Term Outcome After Penetrating Keratoplasty in a Pedigree With the G177E Mutation in the UBIAD1 Gene for Schnyder Corneal Dystrophy. Cornea 2018; 37:554-559. [PMID: 29319599 DOI: 10.1097/ico.0000000000001511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE To investigate the long-term surgical outcome after penetrating keratoplasty in 5 patients from 1 pedigree with Schnyder corneal dystrophy (SCD), resulting from the same UbiA prenyltransferase domain containing 1 (UBIAD1) mutation. METHODS This retrospective study involved 6 eyes of 5 patients who underwent penetrating keratoplasty for treatment of SCD. Postoperative surgical outcome measures included the analysis of best-corrected visual acuity (BCVA), corneal endothelial cell density, and the rates of corneal graft rejection and disease recurrence. Genomic DNA was extracted from whole peripheral blood samples obtained from each patient at the time of surgery, and mutation analysis of the UBIAD1 gene was then performed. RESULTS All patients were found to have the same G177E mutation in the UBIAD1 gene. Mean patient age at the time of surgery was 61.5 ± 10.4 years (range, 49-72 yrs), and mean postoperative follow-up period was 8.8 ± 3.1 years (range, 3-11 yrs). Preoperatively, BCVA ranged from logarithm of the minimum angle of resolution (logMAR) 1.7 to logMAR 0.22; yet, it was found that BCVA had improved to logMAR 0.02 at 3 years postoperatively. Mean corneal endothelial cell density at 3, 5, and 8 years postoperatively was 2181, 1783, and 910 cells/mm, respectively. In all eyes, no disease recurrence or corneal graft rejection was observed during the follow-up period, and graft transparency was maintained. CONCLUSIONS Our findings show that the corneal grafts in the reported SCD pedigree remained clear with no rejection or disease recurrence over the long term.
Collapse
|
32
|
Siebelmann S, Scholz P, Sonnenschein S, Bachmann B, Matthaei M, Cursiefen C, Heindl LM. Anterior segment optical coherence tomography for the diagnosis of corneal dystrophies according to the IC3D classification. Surv Ophthalmol 2018; 63:365-380. [DOI: 10.1016/j.survophthal.2017.08.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/31/2017] [Accepted: 08/03/2017] [Indexed: 11/30/2022]
|
33
|
Schumacher MM, Jun DJ, Johnson BM, DeBose-Boyd RA. UbiA prenyltransferase domain-containing protein-1 modulates HMG-CoA reductase degradation to coordinate synthesis of sterol and nonsterol isoprenoids. J Biol Chem 2017; 293:312-323. [PMID: 29167270 DOI: 10.1074/jbc.ra117.000423] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 11/20/2017] [Indexed: 12/17/2022] Open
Abstract
UBIAD1 (UbiA prenyltransferase domain-containing protein-1) utilizes geranylgeranyl pyrophosphate (GGpp) to synthesize vitamin K2 We previously reported that sterols stimulate binding of UBIAD1 to endoplasmic reticulum (ER)-localized 3-hydroxy-3-methylglutaryl (HMG) CoA reductase. UBIAD1 binding inhibits sterol-accelerated, ER-associated degradation (ERAD) of reductase, one of several mechanisms for feedback control of this rate-limiting enzyme in the branched pathway that produces cholesterol and nonsterol isoprenoids such as GGpp. Accumulation of GGpp in ER membranes triggers release of UBIAD1 from reductase, permitting its maximal ERAD and ER-to-Golgi transport of UBIAD1. Mutant UBIAD1 variants associated with Schnyder corneal dystrophy (SCD), a human disorder characterized by corneal accumulation of cholesterol, resist GGpp-induced release from reductase and remain sequestered in the ER to block reductase ERAD. Using lines of genetically manipulated cells, we now examine consequences of UBIAD1 deficiency and SCD-associated UBIAD1 on reductase ERAD and cholesterol synthesis. Our results indicated that reductase becomes destabilized in the absence of UBIAD1, resulting in reduced cholesterol synthesis and intracellular accumulation. In contrast, an SCD-associated UBIAD1 variant inhibited reductase ERAD, thereby stabilizing the enzyme and contributing to enhanced synthesis and intracellular accumulation of cholesterol. Finally, we present evidence that GGpp-regulated, ER-to-Golgi transport enables UBIAD1 to modulate reductase ERAD such that synthesis of nonsterol isoprenoids is maintained in sterol-replete cells. These findings further establish UBIAD1 as a central player in the reductase ERAD pathway and regulation of isoprenoid synthesis. They also indicate that UBIAD1-mediated inhibition of reductase ERAD underlies cholesterol accumulation associated with SCD.
Collapse
Affiliation(s)
- Marc M Schumacher
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9046
| | - Dong-Jae Jun
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9046
| | - Brittany M Johnson
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9046
| | - Russell A DeBose-Boyd
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9046.
| |
Collapse
|
34
|
Johnson BM, DeBose-Boyd RA. Underlying mechanisms for sterol-induced ubiquitination and ER-associated degradation of HMG CoA reductase. Semin Cell Dev Biol 2017; 81:121-128. [PMID: 29107682 DOI: 10.1016/j.semcdb.2017.10.019] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 10/19/2017] [Indexed: 11/30/2022]
Abstract
Accelerated ubiquitination and subsequent endoplasmic reticulum (ER)-associated degradation (ERAD) constitute one of several mechanisms for feedback control of HMG CoA reductase, the rate-limiting enzyme in synthesis of cholesterol and nonsterol isoprenoids. This ERAD is initiated by the accumulation of certain sterols in ER membranes, which trigger binding of reductase to ER membrane proteins called Insigs. Insig-associated ubiquitin ligases facilitate ubiquitination of reductase, marking the enzyme for extraction across the ER membrane through a reaction that is augmented by nonsterol isoprenoids. Once extracted, ubiquitinated reductase becomes dislocated into the cytosol for degradation by 26S proteasomes. In this review, we will highlight several advances in the understanding of reductase ERAD, which includes the discovery for a role of the vitamin K2 synthetic enzyme UBIAD1 in the reaction and demonstration that sterol-accelerated ERAD significantly contributes to feedback regulation of reductase and cholesterol metabolism in livers of whole animals.
Collapse
Affiliation(s)
- Brittany M Johnson
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, United States
| | - Russell A DeBose-Boyd
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, United States.
| |
Collapse
|
35
|
Abeshi A, Fanelli F, Beccari T, Dundar M, Viola F, Colombo L, Bertelli M. Genetic testing for corneal dystrophies and other corneal Mendelian diseases. THE EUROBIOTECH JOURNAL 2017. [DOI: 10.24190/issn2564-615x/2017/s1.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Abstract
We studied the scientific literature and disease guidelines in order to summarize the clinical utility of the genetic test for corneal dystrophies and other Mendelian corneal diseases (CDs). CDs are mostly inherited in an autosomal dominant manner (autosomal recessive inheritance is rare). The overall prevalence is currently unknown. CDs are caused by mutations in the AGBL1, CHST6, COL8A2, DCN, GSN, KRT12, KRT3, NLRP1, PAX6, PIKFYVE, PRDM5, SLC4A11, TACSTD2, TCF4, TGFBI, UBIAD1, VSX1, ZEB1, and ZNF469 genes. Clinical diagnosis is based on clinical findings, ophthalmological examination, confocal microscopy and slit-lamp biomicroscopy. The genetic test is useful for confirming diagnosis and for differential diagnosis, couple risk assessment and access to clinical trials.
Collapse
Affiliation(s)
- Andi Abeshi
- MAGI Balkans, Tirana , Albania
- MAGI’S Lab, Rovereto , Italy
| | | | - Tommaso Beccari
- Department of Pharmaceutical Sciences, University of Perugia, Perugia , Italy
| | - Munis Dundar
- Department of Medical Genetics, Erciyes University Medical School, Kayseri , Turkey
| | - Francesco Viola
- Department of Clinical Sciences and Community Health, University of Milan, Ophthalmological Unit, IRCCS-Ca Granda Foundation-Ospedale Maggiore Policlinico, Milan , Italy
| | - Leonardo Colombo
- Department of Ophthalmology, ASST Santi Paolo e Carlo, University of Milan, Milan , Italy
| | | |
Collapse
|
36
|
Opsin-Mediated Inhibition of Bacterioruberin Synthesis in Halophilic Archaea. J Bacteriol 2017; 199:JB.00303-17. [PMID: 28784816 DOI: 10.1128/jb.00303-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 07/31/2017] [Indexed: 01/21/2023] Open
Abstract
Halophilic archaea often inhabit environments with limited oxygen, and many produce ion-pumping rhodopsin complexes that allow them to maintain electrochemical gradients when aerobic respiration is inhibited. Rhodopsins require a protein, an opsin, and an organic cofactor, retinal. We previously demonstrated that in Halobacterium salinarum, bacterioopsin (BO), when not bound by retinal, inhibits the production of bacterioruberin, a biochemical pathway that shares intermediates with retinal biosynthesis. In this work, we used heterologous expression in a related halophilic archaeon, Haloferax volcanii, to demonstrate that BO is sufficient to inhibit bacterioruberin synthesis catalyzed by the H. salinarum lycopene elongase (Lye) enzyme. This inhibition was observed both in liquid culture and in a novel colorimetric assay to quantify bacterioruberin abundance based on the colony color. Addition of retinal to convert BO to the bacteriorhodopsin complex resulted in a partial rescue of bacterioruberin production. To explore if this regulatory mechanism occurs in other organisms, we expressed a Lye homolog and an opsin from Haloarcula vallismortis in H. volcaniiH. vallismortis cruxopsin-3 expression inhibited bacterioruberin synthesis catalyzed by H. vallismortis Lye but had no effect when bacterioruberin synthesis was catalyzed by H. salinarum or H. volcanii Lye. Conversely, H. salinarum BO did not inhibit H. vallismortis Lye activity. Together, our data suggest that opsin-mediated inhibition of Lye is potentially widespread and represents an elegant regulatory mechanism that allows organisms to efficiently utilize ion-pumping rhodopsins obtained through lateral gene transfer.IMPORTANCE Many enzymes are complexes of proteins and nonprotein organic molecules called cofactors. To ensure efficient formation of functional complexes, organisms must regulate the production of proteins and cofactors. To study this regulation, we used bacteriorhodopsin from the archaeon Halobacterium salinarum Bacteriorhodopsin consists of the bacterioopsin protein and a retinal cofactor. In this article, we further characterize a novel regulatory mechanism in which bacterioopsin promotes retinal production by inhibiting a reaction that consumes lycopene, a retinal precursor. By expressing H. salinarum genes in a different organism, Haloferax volcanii, we demonstrated that bacterioopsin alone is sufficient for this inhibition. We also found that an opsin from Haloarcula vallismortis has inhibitory activity, suggesting that this regulatory mechanism might be found in other organisms.
Collapse
|
37
|
Yan B, Sun Y, Wang J. Depletion of ubiA prenyltransferase domain containing 1 expression promotes angiotensin II‑induced hypertrophic response in AC16 human myocardial cells via modulating the expression levels of coenzyme Q10 and endothelial nitric oxide synthase. Mol Med Rep 2017; 16:6910-6915. [PMID: 28901410 DOI: 10.3892/mmr.2017.7407] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 05/22/2017] [Indexed: 11/06/2022] Open
Abstract
UbiA prenyltransferase domain containing 1 (UBIAD1) is closely associated with cardiovascular diseases. However, at the cellular level, little is known about how UBIAD1 is expressed and functions in cardiomyocyte hypertrophy. The aim of the present study was to investigate the expression and role of UBIAD1 in angiotensin II (Ang II)‑induced hypertrophy in AC16 cardiomyoblast cells. The loss‑of‑function approach was used to knock down UBIAD1 in vehicle‑ and Ang II‑stimulated AC16 cells. The levels of atrial natriuretic factor (ANF) and caspase-3 were measured and compared between vehicle‑ and Ang II‑treated AC16 cells pretreated with control siRNA or siRNA against UBIAD1. In addition, the levels of coenzyme Q10 (CoQ10) and endothelial nitric oxide synthase (eNOS) were evaluated and compared between these groups. Ang II induced hypertrophy and apoptosis in AC16 cells, accompanied by increased expression of ANF and caspase-3, and decreased expression of UBIAD1. These effects were potentiated by UBIAD1 knockdown. In addition, Ang II treatment suppressed the expression of CoQ10 and eNOS, as well as the production of NO, and these inhibitory effects were also enhanced by UBIAD1 knockdown. Thus, silencing of UBIAD1 expression promotes a myocardial hypertrophic response to Ang II stimulation, in part, by suppressing the expression of CoQ10 and eNOS.
Collapse
Affiliation(s)
- Bingju Yan
- Department of Cardiology, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Yingxian Sun
- Department of Cardiology, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Jun Wang
- Department of Cardiology General Surgery, First Hospital of Liaoning Medical University, Jinzhou, Liaoning 121000, P.R. China
| |
Collapse
|
38
|
Abstract
Vitamin K is a cofactor for γ-glutamyl carboxylase, which catalyzes the posttranslational conversion of specific glutamyl residues to γ-carboxyglutamyl residues in a variety of vitamin K-dependent proteins (VKDPs) involved in blood coagulation, bone and cartilage metabolism, signal transduction, and cell proliferation. Despite the great advances in the genetic, structural, and functional studies of VKDPs as well as the enzymes identified as part of the vitamin K cycle which enable it to be repeatedly recycled within the cells, little is known of the identity and roles of key regulators of vitamin K metabolism in mammals and humans. This review focuses on new insights into the molecular mechanisms underlying the intestinal absorption and in vivo tissue conversion of vitamin K1 to menaquinone-4 (MK-4) with special emphasis on two major advances in the studies of intestinal vitamin K transporters in enterocytes and a tissue MK-4 biosynthetic enzyme UbiA prenyltransferase domain-containing protein 1 (UBIAD1), which participates in the in vivo conversion of a fraction of dietary vitamin K1 to MK-4 in mammals and humans, although it remains uncertain whether UBIAD1 functions as a key regulator of intracellular cholesterol metabolism, bladder and prostate tumor cell progression, vascular integrity, and protection from oxidative stress.
Collapse
|
39
|
Yang Y, Ke N, Liu S, Li W. Methods for Structural and Functional Analyses of Intramembrane Prenyltransferases in the UbiA Superfamily. Methods Enzymol 2016; 584:309-347. [PMID: 28065269 DOI: 10.1016/bs.mie.2016.10.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The UbiA superfamily is a group of intramembrane prenyltransferases that generate lipophilic compounds essential in biological membranes. These compounds, which include various quinones, hemes, chlorophylls, and vitamin E, participate in electron transport and function as antioxidants, as well as acting as structural lipids of microbial cell walls and membranes. Prenyltransferases producing these compounds are involved in important physiological processes and human diseases. These UbiA superfamily members differ significantly in their enzymatic activities and substrate selectivities. This chapter describes examples of methods that can be used to group these intramembrane enzymes, analyze their activity, and screen and crystallize homolog proteins for structure determination. Recent structures of two archaeal homologs are compared with structures of soluble prenyltransferases to show distinct mechanisms used by the UbiA superfamily to control enzymatic activity in membranes.
Collapse
Affiliation(s)
- Y Yang
- Washington University School of Medicine, St. Louis, MO, United States
| | - N Ke
- New England Biolabs, Ipswich, MA, United States
| | - S Liu
- Washington University School of Medicine, St. Louis, MO, United States
| | - W Li
- Washington University School of Medicine, St. Louis, MO, United States.
| |
Collapse
|
40
|
Dufrisne MB, Petrou VI, Clarke OB, Mancia F. Structural basis for catalysis at the membrane-water interface. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:1368-1385. [PMID: 27913292 DOI: 10.1016/j.bbalip.2016.11.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 11/22/2016] [Accepted: 11/23/2016] [Indexed: 11/27/2022]
Abstract
The membrane-water interface forms a uniquely heterogeneous and geometrically constrained environment for enzymatic catalysis. Integral membrane enzymes sample three environments - the uniformly hydrophobic interior of the membrane, the aqueous extramembrane region, and the fuzzy, amphipathic interfacial region formed by the tightly packed headgroups of the components of the lipid bilayer. Depending on the nature of the substrates and the location of the site of chemical modification, catalysis may occur in each of these environments. The availability of structural information for alpha-helical enzyme families from each of these classes, as well as several beta-barrel enzymes from the bacterial outer membrane, has allowed us to review here the different ways in which each enzyme fold has adapted to the nature of the substrates, products, and the unique environment of the membrane. Our focus here is on enzymes that process lipidic substrates. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop.
Collapse
Affiliation(s)
- Meagan Belcher Dufrisne
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Vasileios I Petrou
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Oliver B Clarke
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA.
| |
Collapse
|
41
|
Lin ZN, Chen J, Cui HP. Characteristics of corneal dystrophies: a review from clinical, histological and genetic perspectives. Int J Ophthalmol 2016; 9:904-13. [PMID: 27366696 DOI: 10.18240/ijo.2016.06.20] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 08/16/2015] [Indexed: 01/16/2023] Open
Abstract
Corneal dystrophy is a common type of hereditary corneal diseases. It includes many types, which have varied pathology, histology and clinical manifestations. Recently, the examination techniques of ophthalmology and gene sequencing advance greatly, which do benefit to our understanding of these diseases. However, many aspects remain still unknown. And due to the poor knowledge of these diseases, the results of the treatments are not satisfoctory. The purpose of this review was to summarize the clinical, histological and genetic characteristics of different types of corneal dystrophies.
Collapse
Affiliation(s)
- Ze-Nan Lin
- Department of Ophthalmology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Jie Chen
- Department of Ophthalmology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Hong-Ping Cui
- Department of Ophthalmology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| |
Collapse
|
42
|
Lin BR, Frausto RF, Vo RC, Chiu SY, Chen JL, Aldave AJ. Identification of the First De Novo UBIAD1 Gene Mutation Associated with Schnyder Corneal Dystrophy. J Ophthalmol 2016; 2016:1968493. [PMID: 27382485 PMCID: PMC4921136 DOI: 10.1155/2016/1968493] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Revised: 05/10/2016] [Accepted: 05/12/2016] [Indexed: 11/17/2022] Open
Abstract
Purpose. To report the identification of the first de novo UBIAD1 missense mutation in an individual with Schnyder corneal dystrophy (SCD). Methods. A slit lamp examination was performed on a 47-year-old woman without a family history of corneal disorders. The proband's parents, two sisters, and son were also examined and genomic DNA from all six individuals was collected. The exons and exon-intron boundaries of UBIAD1 were screened using Sanger sequencing. Identified mutations were screened for in 200 control chromosomes. In silico analysis predicted the impact of identified mutations on protein function and structure. Results. Slit lamp examination of the proband revealed findings consistent with SCD. Corneas of the family members appeared unaffected. Screening of UBIAD1 in the proband identified a novel heterozygous c.308C>T mutation, predicted to encode the missense amino acid substitution p.(Thr103Ile). This mutation was not identified in any of the family members or in 200 control chromosomes and was predicted to be damaging to normal protein function and structure. Conclusions. We present a novel heterozygous de novo missense mutation in UBIAD1, p.(Thr103Ile), identified in a patient with classic clinical features of SCD. This highlights the value of genetic testing in clinical diagnostic settings, even in the absence of a positive family history.
Collapse
Affiliation(s)
- Benjamin R. Lin
- Stein Eye Institute, David Geffen School of Medicine at UCLA, 100 Stein Plaza, Los Angeles, CA 90095-7003, USA
| | - Ricardo F. Frausto
- Stein Eye Institute, David Geffen School of Medicine at UCLA, 100 Stein Plaza, Los Angeles, CA 90095-7003, USA
| | - Rosalind C. Vo
- Stein Eye Institute, David Geffen School of Medicine at UCLA, 100 Stein Plaza, Los Angeles, CA 90095-7003, USA
| | - Stephan Y. Chiu
- Stein Eye Institute, David Geffen School of Medicine at UCLA, 100 Stein Plaza, Los Angeles, CA 90095-7003, USA
| | - Judy L. Chen
- Stein Eye Institute, David Geffen School of Medicine at UCLA, 100 Stein Plaza, Los Angeles, CA 90095-7003, USA
| | - Anthony J. Aldave
- Stein Eye Institute, David Geffen School of Medicine at UCLA, 100 Stein Plaza, Los Angeles, CA 90095-7003, USA
| |
Collapse
|
43
|
Crispin SM. Lipids and the eye. Vet J 2016; 212:90-8. [PMID: 27117400 DOI: 10.1016/j.tvjl.2016.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/19/2016] [Accepted: 03/17/2016] [Indexed: 10/22/2022]
|
44
|
Schumacher MM, Jun DJ, Jo Y, Seemann J, DeBose-Boyd RA. Geranylgeranyl-regulated transport of the prenyltransferase UBIAD1 between membranes of the ER and Golgi. J Lipid Res 2016; 57:1286-99. [PMID: 27121042 DOI: 10.1194/jlr.m068759] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Indexed: 11/20/2022] Open
Abstract
UbiA prenyltransferase domain-containing protein-1 (UBIAD1) utilizes geranylgeranyl pyrophosphate (GGpp) to synthesize the vitamin K2 subtype menaquinone-4. Previously, we found that sterols trigger binding of UBIAD1 to endoplasmic reticulum (ER)-localized HMG-CoA reductase, the rate-limiting enzyme in synthesis of cholesterol and nonsterol isoprenoids, including GGpp. This binding inhibits sterol-accelerated degradation of reductase, which contributes to feedback regulation of the enzyme. The addition to cells of geranylgeraniol (GGOH), which can become converted to GGpp, triggers release of UBIAD1 from reductase, allowing for its maximal degradation and permitting ER-to-Golgi transport of UBIAD1. Here, we further characterize geranylgeranyl-regulated transport of UBIAD1. Results of this characterization support a model in which UBIAD1 continuously cycles between the ER and medial-trans Golgi of isoprenoid-replete cells. Upon sensing a decline of GGpp in ER membranes, UBIAD1 becomes trapped in the organelle where it inhibits reductase degradation. Mutant forms of UBIAD1 associated with Schnyder corneal dystrophy (SCD), a human eye disease characterized by corneal accumulation of cholesterol, are sequestered in the ER and block reductase degradation. Collectively, these findings disclose a novel sensing mechanism that allows for stringent metabolic control of intracellular trafficking of UBIAD1, which directly modulates reductase degradation and becomes disrupted in SCD.
Collapse
Affiliation(s)
- Marc M Schumacher
- Departments of Molecular Genetics University of Texas Southwestern Medical Center, Dallas, TX 75390-9046
| | - Dong-Jae Jun
- Departments of Molecular Genetics University of Texas Southwestern Medical Center, Dallas, TX 75390-9046
| | - Youngah Jo
- Departments of Molecular Genetics University of Texas Southwestern Medical Center, Dallas, TX 75390-9046
| | - Joachim Seemann
- Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046
| | - Russell A DeBose-Boyd
- Departments of Molecular Genetics University of Texas Southwestern Medical Center, Dallas, TX 75390-9046
| |
Collapse
|
45
|
Li W. Bringing Bioactive Compounds into Membranes: The UbiA Superfamily of Intramembrane Aromatic Prenyltransferases. Trends Biochem Sci 2016; 41:356-370. [PMID: 26922674 DOI: 10.1016/j.tibs.2016.01.007] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 01/23/2016] [Accepted: 01/29/2016] [Indexed: 11/25/2022]
Abstract
The UbiA superfamily of intramembrane prenyltransferases catalyzes a key biosynthetic step in the production of ubiquinones, menaquinones, plastoquinones, hemes, chlorophylls, vitamin E, and structural lipids. These lipophilic compounds serve as electron and proton carriers for cellular respiration and photosynthesis, as antioxidants to reduce cell damage, and as structural components of microbial cell walls and membranes. This article reviews the biological functions and enzymatic activities of representative members of the superfamily, focusing on the remarkable recent research progress revealing that the UbiA superfamily is centrally implicated in several important physiological processes and human diseases. Because prenyltransferases in this superfamily have distinctive substrate preferences, two recent crystal structures are compared to illuminate the general mechanism for substrate recognition.
Collapse
Affiliation(s)
- Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
| |
Collapse
|
46
|
Role of UBIAD1 in Intracellular Cholesterol Metabolism and Vascular Cell Calcification. PLoS One 2016; 11:e0149639. [PMID: 26890002 PMCID: PMC4758632 DOI: 10.1371/journal.pone.0149639] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 02/03/2016] [Indexed: 01/04/2023] Open
Abstract
Vascular calcification is an important risk factor associated with mortality among patients with chronic kidney disease. Intracellular cholesterol metabolism is involved in the process of vascular cell calcification. In this study, we investigated the role of UbiA prenyltransferase domain containing 1 (UBIAD1) in intracellular cholesterol metabolism and vascular cell calcification, and identified its subcellular location. Primary human umbilical vein smooth muscle cells (HUVSMCs) were incubated with either growth medium (1.4 mmol/L Pi) or calcification medium (CM) (3.0 mmol/L Pi). Under treatment with CM, HUVSMCs were further incubated with exogenous cholesterol, or menaquinone-4, a product of UBIAD1. The plasmid and small interfering RNA were transfected in HUVSMCs to alter the expression of UBIAD1. Matrix calcium quantitation, alkaline phosphatase activity, intracellular cholesterol level and menaquinone-4 level were measured. The expression of several genes involved in cholesterol metabolism were analyzed. Using an anti-UBIAD1 antibody, an endoplasmic reticulum marker and a Golgi marker, the subcellular location of UBIAD1 in HUVSMCs was analyzed. CM increased matrix calcium, alkaline phosphatase activity and intracellular cholesterol level, and reduced UBIAD1 expression and menaquinone-4 level. Addition of cholesterol contributed to increased matrix calcification and alkaline phosphatase activity in a dose-dependent manner. Elevated expression of UBIAD1 or menaquinone-4 in HUVSMCs treated with CM significantly reduced intracellular cholesterol level, matrix calcification and alkaline phosphatase activity, but increased menaquinone-4 level. Elevated expression of UBIAD1 or menaquinone-4 reduced the gene expression of sterol regulatory element-binding protein-2, and increased gene expression of ATP binding cassette transporters A1, which are in charge of cholesterol synthesis and efflux. UBIAD1 co-localized with the endoplasmic reticulum marker and the Golgi marker in HUVSMCs. In conclusion, high intracellular cholesterol content contributes to phosphate-induced vascular cell differentiation and calcification. UBIAD1 or menaquinone-4 could decrease vascular cell differentiation and calcification, probably via its potent role of inversely modulating cellular cholesterol.
Collapse
|
47
|
Sacchetti M, Macchi I, Tiezzi A, La Cava M, Massaro-Giordano G, Lambiase A. Pathophysiology of Corneal Dystrophies: From Cellular Genetic Alteration to Clinical Findings. J Cell Physiol 2015; 231:261-9. [DOI: 10.1002/jcp.25082] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 06/19/2015] [Indexed: 02/04/2023]
Affiliation(s)
- Marta Sacchetti
- Cornea and Ocular Surface Unit; Ospedale San Raffaele, IRCCS-Milan; Milano Italy
| | - Ilaria Macchi
- Department of Ophthalmology; University of Rome “Campus Bio-Medico”; Rome Italy
| | - Alessandro Tiezzi
- Section of Ophthalmology, Department of Sense Organs; University of Rome “Sapienza”; Rome Italy
| | - Maurizio La Cava
- Section of Ophthalmology, Department of Sense Organs; University of Rome “Sapienza”; Rome Italy
| | | | - Alessandro Lambiase
- Section of Ophthalmology, Department of Sense Organs; University of Rome “Sapienza”; Rome Italy
| |
Collapse
|
48
|
Kim EK, Lee H, Choi SI. Molecular Pathogenesis of Corneal Dystrophies: Schnyder Dystrophy and Granular Corneal Dystrophy type 2. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 134:99-115. [PMID: 26310152 DOI: 10.1016/bs.pmbts.2015.05.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The International Committee for Classification of Corneal Dystrophies (IC3D) provides updated data to ophthalmologists by incorporating traditional definitions of corneal dystrophies with new genetic, clinical, and pathologic information. Recent advances in the genetics of corneal dystrophies facilitate more precise classifications and elucidate each classification's molecular mechanisms. Unfortunately, the molecular mechanisms and underlying pathogenic mechanisms have remained obscure, with the exception of Schnyder corneal dystrophy (CD), granular CD type 2 (GCD2), and Fuch's endothelial CD. Here, we review the pathogenesis of Schnyder CD and GCD2.
Collapse
Affiliation(s)
- Eung Kweon Kim
- Department of Ophthalmology, Vision Research Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea; Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea; BK21 Plus Project for Medical Science and Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea.
| | - Hun Lee
- Department of Ophthalmology, Vision Research Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea; Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Seung-Il Choi
- Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
| |
Collapse
|
49
|
Hirota Y, Nakagawa K, Sawada N, Okuda N, Suhara Y, Uchino Y, Kimoto T, Funahashi N, Kamao M, Tsugawa N, Okano T. Functional characterization of the vitamin K2 biosynthetic enzyme UBIAD1. PLoS One 2015; 10:e0125737. [PMID: 25874989 PMCID: PMC4398444 DOI: 10.1371/journal.pone.0125737] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 03/25/2015] [Indexed: 01/23/2023] Open
Abstract
UbiA prenyltransferase domain-containing protein 1 (UBIAD1) plays a significant role in vitamin K2 (MK-4) synthesis. We investigated the enzymological properties of UBIAD1 using microsomal fractions from Sf9 cells expressing UBIAD1 by analysing MK-4 biosynthetic activity. With regard to UBIAD1 enzyme reaction conditions, highest MK-4 synthetic activity was demonstrated under basic conditions at a pH between 8.5 and 9.0, with a DTT ≥0.1 mM. In addition, we found that geranyl pyrophosphate and farnesyl pyrophosphate were also recognized as a side-chain source and served as a substrate for prenylation. Furthermore, lipophilic statins were found to directly inhibit the enzymatic activity of UBIAD1. We analysed the aminoacid sequences homologies across the menA and UbiA families to identify conserved structural features of UBIAD1 proteins and focused on four highly conserved domains. We prepared protein mutants deficient in the four conserved domains to evaluate enzyme activity. Because no enzyme activity was detected in the mutants deficient in the UBIAD1 conserved domains, these four domains were considered to play an essential role in enzymatic activity. We also measured enzyme activities using point mutants of the highly conserved aminoacids in these domains to elucidate their respective functions. We found that the conserved domain I is a substrate recognition site that undergoes a structural change after substrate binding. The conserved domain II is a redox domain site containing a CxxC motif. The conserved domain III is a hinge region important as a catalytic site for the UBIAD1 enzyme. The conserved domain IV is a binding site for Mg2+/isoprenyl side-chain. In this study, we provide a molecular mapping of the enzymological properties of UBIAD1.
Collapse
Affiliation(s)
- Yoshihisa Hirota
- Department of Hygienic Sciences, Kobe Pharmaceutical University, Kobe, Japan
- Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan
- * E-mail: (YH); (TO)
| | - Kimie Nakagawa
- Department of Hygienic Sciences, Kobe Pharmaceutical University, Kobe, Japan
| | - Natsumi Sawada
- Department of Hygienic Sciences, Kobe Pharmaceutical University, Kobe, Japan
| | - Naoko Okuda
- Department of Hygienic Sciences, Kobe Pharmaceutical University, Kobe, Japan
| | - Yoshitomo Suhara
- Department of Bioscience and Engineering, Shibaura Institute of Technology, Saitama, Japan
| | - Yuri Uchino
- Department of Hygienic Sciences, Kobe Pharmaceutical University, Kobe, Japan
| | - Takashi Kimoto
- Department of Hygienic Sciences, Kobe Pharmaceutical University, Kobe, Japan
| | - Nobuaki Funahashi
- Department of Hygienic Sciences, Kobe Pharmaceutical University, Kobe, Japan
| | - Maya Kamao
- Department of Hygienic Sciences, Kobe Pharmaceutical University, Kobe, Japan
| | - Naoko Tsugawa
- Department of Hygienic Sciences, Kobe Pharmaceutical University, Kobe, Japan
| | - Toshio Okano
- Department of Hygienic Sciences, Kobe Pharmaceutical University, Kobe, Japan
- * E-mail: (YH); (TO)
| |
Collapse
|
50
|
Schumacher MM, Elsabrouty R, Seemann J, Jo Y, DeBose-Boyd RA. The prenyltransferase UBIAD1 is the target of geranylgeraniol in degradation of HMG CoA reductase. eLife 2015; 4. [PMID: 25742604 PMCID: PMC4374513 DOI: 10.7554/elife.05560] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 03/04/2015] [Indexed: 01/18/2023] Open
Abstract
Schnyder corneal dystrophy (SCD) is an autosomal dominant disorder in humans characterized by abnormal accumulation of cholesterol in the cornea. SCD-associated mutations have been identified in the gene encoding UBIAD1, a prenyltransferase that synthesizes vitamin K2. Here, we show that sterols stimulate binding of UBIAD1 to the cholesterol biosynthetic enzyme HMG CoA reductase, which is subject to sterol-accelerated, endoplasmic reticulum (ER)-associated degradation augmented by the nonsterol isoprenoid geranylgeraniol through an unknown mechanism. Geranylgeraniol inhibits binding of UBIAD1 to reductase, allowing its degradation and promoting transport of UBIAD1 from the ER to the Golgi. CRISPR-CAS9-mediated knockout of UBIAD1 relieves the geranylgeraniol requirement for reductase degradation. SCD-associated mutations in UBIAD1 block its displacement from reductase in the presence of geranylgeraniol, thereby preventing degradation of reductase. The current results identify UBIAD1 as the elusive target of geranylgeraniol in reductase degradation, the inhibition of which may contribute to accumulation of cholesterol in SCD. DOI:http://dx.doi.org/10.7554/eLife.05560.001 People with a rare genetic disorder called ‘Schnyder corneal dystrophy’ gradually lose their vision, because their corneas become increasingly cloudy. This cloudiness is caused by a build-up of excessive amounts of cholesterol, and the disorder itself is caused by mutations in a gene that encodes a protein called UBIAD1. Researchers have previously discovered that the UBIAD1 protein is involved in making vitamin K2, but it is not clear how this protein also helps to control cholesterol levels in the cornea. An enzyme called HMG CoA reductase makes a molecule that is used to make cholesterol and many other similar sterol molecules. A ‘feedback loop’ operates in cells to control the amount of the reductase and prevent cholesterol from becoming too high or too low. Sterol molecules, together with another molecule called geranylgeraniol, participate in this feedback loop by promoting the destruction of the reductase enzyme. Here, Schumacher et al. reveal a link between UBIAD1 and the reductase that may explain how UBIAD1 contributes to the production of excess cholesterol in patients with Schnyder corneal dystrophy. The experiments show that, in the presence of sterol molecules, UBIAD1 can bind to HMG CoA reductase to protect the reductase from being destroyed by other proteins. Geranylgeraniol—which stops the UBIAD1 protein from binding to the enzyme—is required to completely destroy the reductase enzyme. However, when UBIAD1 is missing, the reductase enzyme is destroyed even in the absence of geranylgeraniol. Furthermore, the experiments show that the genetic mutations linked to Schnyder corneal dystrophy lead to the production of versions of the UBIAD1 protein that bind to the reductase enzyme even when geranylgeraniol molecules are present. This prevents the normal breakdown of the reductase enzyme, which could lead to the build up of cholesterol in the cornea of individuals with the disorder. Schumacher et al.'s findings show that the UBIAD1 protein helps to control the levels of cholesterol in cells by protecting the HMG CoA reductase enzyme from destruction. These findings may aid the development of new therapies to lower cholesterol levels in cells, which may help patients with Schnyder's corneal dystrophy and other conditions caused by high cholesterol levels. DOI:http://dx.doi.org/10.7554/eLife.05560.002
Collapse
Affiliation(s)
- Marc M Schumacher
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Rania Elsabrouty
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Joachim Seemann
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Youngah Jo
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Russell A DeBose-Boyd
- Department of Molecular Genetics, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
| |
Collapse
|